$$2n^2 = 2$$ \times $$3^2 = 18$

$$(6 \times 12.01) + (12 \times 1.01) + (6 \times 16.00) = 180.16 g/$$mol

$$2.45 \text{ mol} \times 6.022 \times 10$$^{23}$$ \text{ atoms/mol} = 1.48 \times 10$$^{24}$$ atoms

Question 1

Which of the following best describes what is happening in the reaction between sodium (Na) and chlorine (Cl) as shown in the first image?

Accepted Answer

Sodium loses an electron to chlorine, forming Na+ and Cl- ions that are held together by electrostatic attraction.

Question 2

According to the octet rule, why are noble gases generally unreactive?

Accepted Answer

They have a full outermost energy level with 8 valence electrons.

Question 3

Which of the following elements is most likely to form a +2 ion?

Accepted Answer

Magnesium (Mg)

Question 4

What is the maximum number of electrons that can occupy the third energy level ($$n=3) of an $$atom?

Accepted Answer

$$2n^2 = 2$$ 	imes $$3^2 = 18$

Question 5

Which of the following statements about electronegativity is correct?

Accepted Answer

Electronegativity increases from left to right across a period and decreases down a group.

Question 6

A molecule of water (H$$_2O) $$has which molecular shape?

Accepted Answer

Bent or V-shaped

Question 7

How many moles of silver atoms are in a pure silver ring containing $$2.80 	imes 10$$^{22}$$ silver atoms?

Accepted Answer

$$4.65 	imes 10$$^{-2}$$ mol

Question 8

Which of the following best explains why metals tend to lose electrons to form cations?

Accepted Answer

Metals have larger atomic radii and lower ionization energies, making it easier to lose electrons.

Question 9

What is the molecular weight of glucose ($$C_6H_{12}O_6$)? (Atomic masses: C = 12.01, H = 1.01, O = 16.00)

Accepted Answer

$$(6 	imes 12.01) + (12 	imes 1.01) + (6 	imes 16.00) = 180.16 g/$$mol

Question 10

Which of the following is a property of ionic compounds?

Accepted Answer

They are composed of positive and negative ions held together by electrostatic forces.

Question 11

How many atoms are in 2.45 mol of copper?

Accepted Answer

$$2.45 	ext{ mol} 	imes 6.022 	imes 10$$^{23}$$ 	ext{ atoms/mol} = 1.48 	imes 10$$^{24}$$ atoms

Question 12

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electrons between two nonmetal atoms.

Question 13

Which element has the highest electronegativity?

Accepted Answer

Fluorine (F)

Question 14

What is the number of valence electrons in a nitrogen atom?

Accepted Answer

5

Question 15

Which of the following best explains why chlorine forms a -1 ion?

Accepted Answer

Chlorine gains one electron to achieve a full octet in its valence shell.

Question 16

Which of the following is the correct formula for calculating the molecular weight of a compound?

Accepted Answer

$$	ext{Molecular Weight} = \sum (	ext{Atomic Mass} 	imes 	ext{Number of Atoms})$$

Question 17

Which of the following best describes Avogadro's number?

Accepted Answer

The number of representative particles in one mole, $$6.022 	imes 10$$^{23}$$.

Question 18

Which of the following elements is most likely to form a covalent bond with oxygen?

Accepted Answer

Hydrogen (H)

Question 19

If you have 100 g of glucose ($$C_6H_{12}O_6$), how many moles do you have? (Molecular weight = 180.16 g/mol)

Accepted Answer

$$100 	ext{ g} / 180.16 	ext{ g/mol} = 0.555$$ mol

Chapter 3 Study Guide: Compounds, Electron Arrangements, and the Mole

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