Q: How many atoms are present in $$2.45$$ moles of copper? (Use Avogadro's number: $$6.022 \times 10$$^{23}$$ atoms/mol)

$$1.47 \times 10$$^{24}$$ atoms

Q: Which of the following is the correct formula for calculating average atomic mass?

$$\text{Average Atomic Mass} = \sum (\text{Fractional abundance} \times \text{isotope exact mass})$$

Q: A sample contains $$1.50$$ moles of silver. How many atoms of silver are present?

$$9.03 \times 10$$^{23}$$ atoms

Question 1

Which subatomic particle determines the atomic number of an element?

Accepted Answer

Proton

Question 2

An atom of sodium (Na) has 11 protons, 12 neutrons, and 11 electrons. What is its mass number?

Accepted Answer

$$23$$

Question 3

Which group in the periodic table contains the most reactive nonmetals?

Accepted Answer

Group 7A

Question 4

What is the average atomic mass of an element with two isotopes: 60% abundance of isotope A (mass = 10 amu) and 40% abundance of isotope B (mass = 12 amu)?

Accepted Answer

$$10.8\ 	ext{amu}$$

Question 5

Which of the following best describes the relationship between atomic mass and molar mass?

Accepted Answer

Atomic mass and molar mass have the same numerical value but different units.

Question 6

How many atoms are present in $$2.45$$ moles of copper? (Use Avogadro's number: $$6.022 	imes 10$$^{23}$$ atoms/mol)

Accepted Answer

$$1.47 	imes 10$$^{24}$$ atoms

Question 7

A pure silver ring contains $$2.80 	imes 10$$^{22}$$ silver atoms. How many moles of silver atoms does it contain?

Accepted Answer

$$0.0465$$ moles

Question 8

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 9

Calculate the number of grams in $$0.90$$ moles of carbon. (Molar mass of carbon = $$12.01\ 	ext{g/mol})$$

Accepted Answer

$$10.81\ 	ext{g}$$

Question 10

Which element group is characterized by being inert and having very low reactivity?

Accepted Answer

Group 8A

Question 11

What is the percent abundance of isotope X if the average atomic mass is $$10.81\ 	ext{amu}$$, isotope X has a mass of $$10.00\ 	ext{amu}$$, and isotope Y has a mass of $$11.00\ 	ext{amu}$$?

Accepted Answer

$$19\%$$

Question 12

Which of the following is the correct formula for calculating average atomic mass?

Accepted Answer

$$	ext{Average Atomic Mass} = \sum (	ext{Fractional abundance} 	imes 	ext{isotope exact mass})$$

Question 13

If you have $$5.57$$ grams of carbon, how many moles do you have? (Molar mass of carbon = $$12.01\ 	ext{g/mol})$$

Accepted Answer

$$0.464$$ moles

Question 14

Which of the following is NOT a property of elements in the same group of the periodic table?

Accepted Answer

They have the same atomic number.

Question 15

Which group in the periodic table contains elements that react vigorously with water?

Accepted Answer

Group 1A

Question 16

How many protons, neutrons, and electrons are in an atom of $$^{24}_{12}	ext{Mg}$$?

Accepted Answer

12 protons, 12 electrons, 12 neutrons

Question 17

Which of the following best describes Avogadro's number?

Accepted Answer

The number of atoms in one mole of a substance

Question 18

A sample contains $$1.50$$ moles of silver. How many atoms of silver are present?

Accepted Answer

$$9.03 	imes 10$$^{23}$$ atoms

Question 19

Which of the following is a correct statement about the periodic table?

Accepted Answer

Elements in the same group have similar chemical properties.

Isotopes, Atomic Mass, the Periodic Table, and the Mole: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards