3.01 Quiz: Atomic Number and the Periodic Law
ps
Which of the following characteristics was not included in Dmitri Mendeleev's periodic table?

distribution of elements determined by electron configuration


What is the primary atomic characteristic that Mendeleev used to organize the periodic table?

atomic mass



Mendeleev left several blank spaces in his original periodic table. What did those spaces represent?

elements that had yet to be discovered


According to the periodic law, what is the relationship between elements and periods?


Element properties repeat from period to period.



Which of these sets of elements has similar properties? Consult the periodic table.
strontium, magnesium, calcium, beryllium

Final answer:

The 93Nb+3 ion has 41 protons, 52 neutrons (assuming the most common isotope of Nb-93), and 38 electrons.

Explanation:

To determine the number of protons, neutrons, and electrons in the 93Nb+3 ion, we use the periodic table to find niobium's (Nb) atomic number and mass number. The atomic number, which is the same as the number of protons, is 41 for niobium. The ion has a 3+ charge (Nb+3), meaning it has lost 3 electrons compared to the neutral atom. Since the neutral atom has the same number of protons and electrons, the Nb+3 ion has 41 protons and 41 - 3 = 38 electrons.

To find the number of neutrons, we need additional information such as the isotope's mass number. However, this was not provided in the question. Typically, we could use the most common isotope for niobium, which is Nb-93 (mass number 93), where the number of neutrons is the mass number minus the atomic number: 93 - 41 = 52 neutrons.

Assuming the most common isotope and no additional isotopic information, the 93Nb+3 ion contains 41 protons, 52 neutrons, and 38 electrons.

Hey there!

Given the reaction:

P4 + 10 Cl2  ------------------ 4 PCl5

Molar mass P4 = 124 g/mol

Number of moles P4:

n = mass of solute / molar mass

n = 24.0 / 124

n = 0.1935  moles of P4

Therefore:

1 mole P4 --------------- 4 moles PCl5

0.1935 moles P4 ------- moles PCl5

moles PCl5 = 0.1935 * 4

= 0.774 moles of PCl5

Hope that helps!

If wheelchairs weren't here then people who need them wouldn't be able to go out and enjoy the world as people do today. People who use hearing aids wouldn't be able to hear anything. They would be deaf, they wouldn't be able to hear voices, music, or anything that people with hearing aids or people who hear normal get to hear. Hope that helps you. If you need more help just let me know!

If wheelchairs were not available then people are not able to move by their own and without hearing aids, people are not able to listen others voice.

Technology in science plays an important role as in the modern era every work or thing is possible by using the technology.

Wheelchairs and hearing aids are the example of technology which helps the people with leg and ear issue respectively. If wheelchairs are not available then people are not able to go anywhere or do work by their own. And without hearing aid, people are not able to communicate as they already have some listening issue.

Hence, without wheelchair and hearing aids people were not able to move and listen by themselves.

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Boil the water to get remove the salt and then use filter paper to remove the microorganisms

Answer:

The answer is reverse osmosis!

Explanation:

I chose this on a test and got it right

Answer:

the more heat the more particle movement i dont think mass has any thing to do with it

Explanation:

From the ideal gas equation,

[tex]PV = nRT[/tex]

where n is number of moles, R is Universal gas constant, P is pressure, V is volume,  and T is temperature of the gas.

The pressure and volume are inversely proportional to each other at constant temperature and number of moles.

Hence, on decreasing the pressure, the volume will increase.

As the hiker reaches a height of a mountain, the pressure would decrease which results in the reestablishment of equilibrium between gas molecules thus resulting in pushing of bag outwards.

Hence, the bag will expand as the hiker reaches the top of the mountain.

I believe this is the electric configuration for magnesium, so, In writing the electron configuration for Magnesium the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the next 2 electrons for magnesium go in the 2s orbital. The next six electrons will go in the 2p orbital. The p orbital can hold up to six electrons. We'll put six in the 2p orbital and then put the remaining two electrons in the 3s. Therefore the Magnesium electron configuration will be 1s22s22p63s2.

The answer is B

The entity which is represented by X in the partial electron configuration of an atom with 12 electrons as shown in 1s² 2s² 2p⁶ X is; 3s²

According to the question, the partial electronic configuration of an atom with 12 electrons is shown as follows;

According to the Aufbau's principle, electrons are filled into orbitals with the lowest energy before those of higher Energy are filled.

The shell with energy level 2 has 2 subshells(orbitals) namely the 2s and 2p orbitals with a maximum of 2 and 6 electrons respectively.

The 2 electrons left will be filled into the 3s orbital.

Therefore, X represents 3s².

The electronic configuration is therefore;

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a gap in the rock layer due to erosion or from no rocks being deposited

geological processes taking place today are the same as those that occurred in the past.  

fossil that record the shape and structure of an organism

each layer is older than the layer above and younger than the layer below it.

the preserved remains or traces of a once living organism.

fossils that record the movement or behavior of an organism.

sediments spread in all directions until they thin out or hit a barrier.

sedimentary rocks are deposited horizontally.

age of rock compared to the ages of rock layers.

age of rocks calculated in years since formed.

words:

1.absolute age

2.body fossil

3.fossil

4.principle of lateral continuity

5.principle of original horizontally

6.principle of superposition

7.relative age  

8.trace fossil

9. unconformity

10.uniformitarianism

Answer is 9,10,2,6,3,8,4,5,7,1

All my answers were correct on this one

Hey there. I did not build a model for you. Below is a picture of a Plant Cell that you could get some ideas from.

Best Of Luck,

     - Ari -

A plant cell is a type of cell found in green plants that is responsible for photosynthesis. It contains a cell wall, chloroplasts, and a central vacuole, which distinguish it from animal cells. Plant cells also include plastids and typically do not have lysosomes or centrosomes.

A plant cell is a type of cell found in green plants that is responsible for performing photosynthesis. It contains various elements that distinguish it from animal cells. Major components include:

Unlike animal cells, plant cells also contain plastids and do not usually have lysosomes or centrosomes.

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Here are three everyday situations which it would be useful to identify unknown substances:

1. When you have two clear substances with no labels yet you are not sure which substance is water and which one is not and not knowing what this unknown chemical might do.

2. A stain on your clothes

3. When you are not feeling well and your sense of taste is not functioning well.

The ways that these can be identified is first, start by the appearance, for example the state, color, texture, etc. And secondly, use your sense of smell. This sense is also helpful in identifying whether the substance is something strong or not.

Everyday identification of an unknown substance can be done using spot tests, measuring optical properties, or additional tests for organic or inorganic compounds, utilizing simple tools such as lasers, protractors, and chemical reagents.

Identifying an unknown substance is crucial in various everyday situations, like determining if a liquid spill is water or some hazardous chemical. One practical method for identification is using a spot test, where a chemical reagent is added to the substance, and the presence of a specific substance is indicated, for example, through a color change. Another approach might involve determining the substance's optical properties using equipment such as a laser or a protractor to measure the substance's refractive index compared to a reference guide.

In situations where a mixture contains more than one substance, additional properties like density could be considered to differentiate substances, but recognizing composite materials would require more complex analysis that considers a combination of characteristics.

For organic or inorganic identification, specific chemical tests that highlight carbon presence could be utilized, as organic compounds characteristically contain carbon. A simple burn test could provide preliminary information: if the sample burns with a yellow flame, it's likely organic, indicating the presence of carbon.

Answer. Statement A is correct statement.

Explanation:

Thomson in his experiment  named Cathode Ray Experiment he found that many of the metals release cathode rays which are negatively charged due to the presence of negatively charged subatomic particles that is electrons.

Rays were allowed to pass between the two oppositely charged plates, he observed that the rays were attracted towards positively charged plates and got repelled by the negatively charged plate.

From which he concluded that the atoms contain small, negatively charged particles known as electrons.

So from the statements provided in the question only statement A tells us about the the observation made by the Thomson in his cathode ray experiment where as other three statements are not in agreement with those observations.

J.J. Thomson's experiments with the cathode ray showed that atoms contain small, negatively charged particles.

The evidence from J.J. Thomson's experiments with the cathode ray that led to the plum pudding model of the atom was option A. The beam was attracted to a positive charge and repelled by a negative charge, showing that atoms contain small, negatively charged particles.

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Have you got to design a business card for Beth? If so what business is it for? Xx

ya know what good for beth! I am happy for "beth" lol wth tho!

A. a mixture is a combination of two or more substances in which each substance retains its own properties.

Answer:

protons

neutrons

helium

Explanation:

it is correct

Answer:

The answer is 12,560  

Explanation:

The orbital period is the time a given cosmic question takes to finish one circle around another protest and applies in space science as a rule to planets or space rocks circling the Sun, moons circling planets, exoplanets circling different stars, or double stars. Mercury, for instance, has an orbital time of 88 days while it takes Jupiter around 11.86 years. The time of the Earth's circle is generally thought to be 365 days as timetables appear.

Answer:

12,560 m/s.

Explanation:

The question is missing:

What is the tangential speed of the satellite?

Tangential speed (Vt) is defined as the length of the arc (s) covered per unit of time (t), that is:

Vt = s/t

The period specifies the time the satellite takes to complete the orbital. The whole circumference has an arc length of 2*π*radius. Replacing into the equation:

Vt = 2*π*4*10^10 m /(2*10^7 s)

Vt = 12,560 m/s

Explanation:

1) Is imposible to determine an element from a simple drawing, more information is need or a higher level of details. Also, a "red blob of atoms" sounds like the  description of a molecule (a union of two or more atoms) that may or may not be formed by only one element.

2) There are 92 natural elements, the other ones are synthetic and/or radioactive. You can identify them in the periodic table because their molecular weights are between ( ).

3) False, a molecule is a particular arrangement of atoms that can be from one or more elements. An element is a particular arrangement of atomic particles (neutrons, protons and electrons.)

304 kg*ms or in ms 84.48 kgm/s

Answer: ≈ 708 ( to 3 s.f.)

Working Out:

First we have to establish a balanced chemical equation that defines the reaction

       4 Al     +    3 O₂    →    2 Al₂O₃

Now, mole =  mass ÷ molar mass

∴ If the mass of Al in the reaction = 375 g

              then the # of moles of Al =  375 g  ÷  27 g/mol

                                                        =  13.889 mol

Also, the mole ratio between Al and Al₂O₃  is  2 : 1  (4 : 2).

As such if moles of Al = 13.889 mol

then #  of moles of Al₂O₃ =  13.889 mol ÷ 2

                                         = 6.944 mol

Since mass = mole × molar mass

Then mass of Al₂O₃ = 6.944 mol × ((27 × 2) + (16 × 3)) g/mol

                                 = 6.944 mol × 102  g/mol

                                 = 708.288 g

Final answer:

375 grams of Al will produce approximately 708 grams of Al₂O₃ when it reacts completely with oxygen, according to the balanced chemical equation 4Al + 3O₂ → 2Al₂O₃.

Explanation:

To find out how many grams of Al₂O₃ will be produced from 375 grams of Al reacting completely, we need to first write the balanced chemical equation involving aluminum and oxygen. The following is the balanced equation for the reaction between oxygen (O₂) and aluminum (Al):

4Al + 3O₂ → 2Al₂O₃.

Next, we need to calculate the molar mass of aluminum, which is approximately 26.98 g/mol. Using this, we can find the number of moles of Al by dividing the given mass by the molar mass:

Moles of Al = 375 g / 26.98 g/mol ≈ 13.90 mol of Al.

According to the balanced equation, 4 moles of Al produce 2 moles of Al₂O₃. Using this stoichiometric ratio, we can find how many moles of Al₂O₃ will be produced:

Moles of Al₂O₃ = (13.90 mol Al) × (2 mol Al₂O₃ / 4 mol Al) ≈ 6.95 mol of Al₂O₃.

Finally, we calculate the mass of Al₂O₃ by multiplying the moles by the molar mass of Al₂O₃ (which is approximately 101.96 g/mol):

Mass of Al₂O₃ = 6.95 mol × 101.96 g/mol ≈ 708 g.

Therefore, 708 grams of Al₂O₃ will be produced when 375 grams of Al react completely, rounded to three significant figures.

full moon fasholi. woodgang

When the Moon is positioned between the Sun and Earth, we see a new moon.

A new moon is where the moon is covered by the sun, invisible to the human eye.

Or, c.

Scientist believe that about 25 of the known elements are essential to life. Just four of these - Carbon (C), Oxygen (O), Hydrogen (H), and Nitrogen (N), - make up about 96% of the human body.

These four elements are found in the basic structure of all biochemical molecules. For example, Glucose is a carbohydrate and it's molecular formula is C6H12O6 - each molecule of glucose is made up of 6 Carbon atoms, 12 Hydrogen atoms and 6 oxygen atoms.

The other elements found can be divided into two main groups - major elements and trace elements.

The human body functions as a result of a large number of the chemical reactions involving compounds of a of these elements.

Understanding how elements and compounds react together is key in our daily lives because it influences how we produce and use materials, maintain health, and generate energy. Knowledge of chemical reactions helps in predicting outcomes, creating new substances and improving products.

Understanding how elements and compounds react together is of great importance in our daily lives as we constantly engage with products and processes resulting from chemical reactions. For instance, compounds are formed when two or more elements chemically combine, like how hydrogen and oxygen form water, or how sodium and chlorine combine to create table salt. This knowledge is essential in the fields of medicine, technology, energy production, and even in food preparation and preservation.

There are over 100 elements that can be combined in myriad ways to form millions of different chemical compounds, each of which has unique physical and chemical properties. Knowing how these elements and compounds interact allows us to predict outcomes, create and improve products, and better understand the world around us.

Furthermore, chemical processes and reactions are integral to our existence, providing sustenance, maintaining our health, producing our electronic devices, and enabling transportation, among other things. For example, the energy we use to heat our homes, drive our cars, and generate electricity often comes from the combustion of certain compounds. This vital process of burning materials for energy release is a chemical reaction.

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I would be c. valence electrons. This is because all atoms want to be chemically stable so elements that have 8 valence electrons are chemically stable like neon or any of the noble gases.

Answer:

Explanation:

In research an unreliable source is the one which cannot be accepted by the scientific community. Such source generally includes the information which is not authentic and correct. Such source may include manipulation or unreliable results. The facts mentioned in some unreliable source are not based upon experimental testing.

C. A plant with chlorophyll a and chlorophyll b will absorb a greater range of light than it would if it had chlorophyll a only.

Chlorophyll a is the primary photosynthetic pigment while chlorophyll b is the accessory pigment that collects energy and passes it on to chlorophyll a.

Chlorophyll a absorbs energy from wavelengths of blue-violet and orange-red light while chlorophyll b absorbs energy from wavelengths of green light.

The problem is about calculating mass using the provided density and volume of an object or substance. In physics, mass is determined by multiplying density by volume, resulting in a mass of 70g in this instance.

The subject of this question is tied to the concept of density, a physical property of matter. In physics, we calculate density by dividing mass by volume.

Here, the density is given as 7g/ml, and the volume is stated as 10ml. Using the provided values, you could rearrange the density formula to find the mass.

Mass is calculated by multiplying density by volume, resulting in a mass of 70g.

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1. This can be due to the dissolving of the solid in liquid and form a solution.

Dissolving is a physical property because dissolving doesn't form new substances and the chemical composition of the solid is not changed.

The color building up over the time can be due to the rate of dissolving of the solid and amount of particles have been dissolved.

Example:

2. This can be due to the chemical reaction between the solid and liquid.

Chemical reaction is a chemical property because from reacting substances new substances can be formed which the chemical formula is different from initial substances.

The color building up over the time can be due to the rate of the reaction and the amount of reactants.

Example:

       Ca(s) + 2H₂O(l) → Ca(OH)₂(aq) + H₂(g)

To determine the empirical formula of a compound with 63.65% nitrogen and 36.35% oxygen, calculate the moles of each element based on their mass percentages and atomic masses. After finding moles, derive the simplest ratio which provides the empirical formula N₂O.

Finding the Empirical Formula

To find the empirical formula of a compound with 63.65% nitrogen and 36.35% oxygen by mass, we will need to perform a few calculations. First, we assume we have 100 grams of the compound. This makes it easy to convert percentage to grams directly, so we have 63.65 grams of nitrogen and 36.35 grams of oxygen. Next, we divide the mass of each element by its atomic mass to find the number of moles of each element: nitrogen (N) has an atomic mass of approximately 14.01 g/mol, and oxygen (O) has an atomic mass of approximately 16.00 g/mol.

For nitrogen: 63.65 g N / 14.01 g/mol N = 4.54 mol N
For oxygen: 36.35 g O / 16.00 g/mol O = 2.27 mol O

Then, we find the simplest ratio of the moles of each element by dividing each by the smallest number of moles we calculated:

Ratio of N to O is 4.54 mol N / 2.27 mol O = 2. Since we are looking for the simplest whole number ratio, the empirical formula is N₂O.

CO32- and OH- are the two most common anions in antacids.

Answer:

negative ions.:

Hydroxyde ion (OH-)

Carbonate ion. (CO3 -- )

Explanation:

Acids generally, when are mixed in water, produces a lot of positive hydrogen protons, also knew as protons (H +) are responsible for raising the pH.

pH is (power of hydrogen), it means the more positive hydrogens ions more acid will be that substance. So the antacid's role, to neutralize these positive charges is to add more negative ions to the solutions.

In the stomach, when the stomach acid is liberated to degrade the food, it produces a lot of these protons (H +). The antacids who helps to neutralize this, most commonly used are, (OH-) and (CO3--).Acids generally, wher ar mixed in water, produce a lot of positive hydrogen protons, also knowed as protons (H+) are responsable for rise the pH.

Actually, pH are (power of hydrogen), it means the more positive hydrogens ions more acid will be that substance. So the antacids role, to neutralize this positive charges is add more negative ions to the solutios.

In the stomach, when the stomach acid are liberate to degradate the food, produces a lot of these protons (H+). The antacids who hepls to neutralize this, most commos used are, (OH-) and (CO3-- ).

This anions can be provide for substances like aluminum hydroxyde, magnesium hydroxyde, aluminium carbonate, and others..

These anions can be provided for substances like aluminum hydroxide, magnesium hydroxide, aluminum carbonate, and others.

The final temperature of the system is 32.4 °C.

heat lost by Pb + heat gained by water = 0

[tex]q_{1} +q_{2} = 0[/tex]

[tex]m_{1}C_{1}\Delta T_{1} + m_{2}C_{2}\Delta T_{2} = 0[/tex]

[tex]q_{1}= m_{1}C_{1}\Delta T_{1} = 21.2 \:\text{g}\times 0.128\: \text{J}^{\circ}\text{C}^{-1}\text{g}\times (T_{f} -113\: ^{\circ}\text{C}) = 2.713T_{f}\: \text{J}^{\circ}\text{C}^{-1}\: -\: 306.6\:\text{J}\cdot\text{g}^{-1}\\[/tex]

[tex]q_{2}= m_{2}C_{2}\Delta T_{2} = 14.8 \:\text{g}\times 4.184\: \text{J}\cdot^{\circ}\text{C}^{-1}\text{g}^{-1}\times (T_{f} -28.9\: ^{\circ}\text{C}) = 61.9\: \Delta T_{f} \: \text{J}^{\circ}\text{C} \:- 1790 \: \text{J}\\[/tex]

Adding [tex]q_{1}[/tex] and [tex]q_{2}[/tex] and combinibg like terms, we get

[tex]168.0\text{T}_{f}\: ^{\circ}\text{C} ^{-1}\:- 2096 = 0]\\[/tex]

[tex]T_{f} = \frac{2096}{68.0 \: ^{\circ}\text{C}^{-1}} = 32.4 ^{\circ}\text{C}\\[/tex]