$$6.02 \times 10$$^{23}$$ \times 24$$

Question 1

Which of the following best explains why elements form compounds according to the octet rule?

Accepted Answer

To achieve a stable arrangement of eight electrons in their valence shell

Question 2

How many valence electrons does a neutral atom of sulfur (S) have?

Accepted Answer

6

Question 3

Which of the following ions is isoelectronic with neon (Ne)?

Accepted Answer

$$\mathrm{F^-}$$

Question 4

A magnesium atom reacts with a nitrogen atom to form an ionic compound. What is the correct formula for this compound?

Accepted Answer

$$\mathrm{Mg_3N_2}$$

Question 5

Which of the following best describes the bond in a molecule of $$\mathrm{H_2O}$$?

Accepted Answer

Polar covalent bonds with a bent molecular shape

Question 6

What is the molar mass of $$\mathrm{Ca(OH)_2}$$?

Accepted Answer

$$74.10\ \mathrm{g/mol}$$

Question 7

Which of the following compounds is named correctly?

Accepted Answer

Dinitrogen tetroxide: $$\mathrm{N_2O_4}$$

Question 8

A sample contains $$210\ \mathrm{g} of $$carbon. How many moles of carbon are present? ($$\mathrm{Molar\ mass\ of\ C = 12.01\ g/mol})$$

Accepted Answer

$$17.5\ \mathrm{mol}$$

Question 9

Which of the following statements about electronegativity is correct?

Accepted Answer

Electronegativity increases from left to right across a period and from bottom to top within a group.

Question 10

Which of the following molecules is nonpolar, despite having polar bonds?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 11

What is the correct name for the compound $$\mathrm{$$CuBr_2$$}$$?

Accepted Answer

Copper (II) bromide

Question 12

Which of the following best describes the geometry and bond angle of methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

Tetrahedral, $$109.5^\circ$$

Question 13

How many protons and electrons are present in an $$\mathrm{O$$^{2-}$$}$$ ion?

Accepted Answer

8 protons, 10 electrons

Question 14

Which of the following is a polyatomic ion?

Accepted Answer

$$\mathrm{NO_3$^-}$$

Question 15

What is the correct formula for the ionic compound formed between aluminum and oxygen?

Accepted Answer

$$\mathrm{Al_2O_3}$$

Question 16

Which of the following best describes the difference between ionic and covalent compounds?

Accepted Answer

Ionic compounds involve electron transfer between metals and nonmetals; covalent compounds involve electron sharing between nonmetals.

Question 17

Which of the following molecules has a trigonal pyramidal shape?

Accepted Answer

$$\mathrm{NH_3$}$$

Question 18

What is the total number of atoms in one mole of glucose ($$\mathrm{C_6H_{12}O_6$}$$)?

Accepted Answer

$$6.02 	imes 10$$^{23}$$ 	imes 24$$

Question 19

Which of the following statements about molecular polarity is correct?

Accepted Answer

A molecule can be nonpolar even if it contains polar bonds, depending on its shape.

Compounds—How Elements Combine: Structure, Bonding, and Molecular Properties

Guida di studio - Domande di pratica