Question 1

Which of the following electron configurations represents a neutral atom of sulfur (S)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^4$$

Question 2

Which of the following elements is expected to have the highest first ionization energy?

Accepted Answer

Chlorine (Cl)

Question 3

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

Accepted Answer

$$Na^+$$

Question 4

Which of the following statements best explains why atomic radius decreases across a period from left to right?

Accepted Answer

The nuclear charge increases, pulling electrons closer.

Question 5

Which of the following elements is paramagnetic?

Accepted Answer

Oxygen ($$O)$$

Question 6

Which of the following pairs of elements would you expect to form an ionic compound?

Accepted Answer

Sodium and Chlorine

Question 7

Which of the following molecules has a Lewis structure with a double bond?

Accepted Answer

$$CO_2$$

Question 8

What is the correct name for the compound $$Na_2SO_4$$?

Accepted Answer

Sodium sulfate

Question 9

Calculate the molar mass of calcium chloride ($$CaCl_2).$$

Accepted Answer

$$111.0\ g/mol$$

Question 10

A sample contains $$0.50$$ moles of $$H_2O. $$What is the mass of the sample?

Accepted Answer

$$9.0\ g$$

Question 11

Which of the following formulas represents a binary molecular compound?

Accepted Answer

$$CO_2$$

Question 12

How many molecules are present in $$36.0\ g of $$water ($$H_2O$$)? ($$M_{H_2O} = 18.0\ g/mol)$$

Accepted Answer

$$1.20 	imes 10$$^{24}$$

Question 13

What is the empirical formula of a compound containing $$40.0\%$$ carbon, $$6.7\%$$ hydrogen, and $$53.3\%$$ oxygen by mass?

Accepted Answer

$$CH_2O$$

Question 14

A compound has an empirical formula of $$CH_2$$ and a molar mass of $$56\ g/mol. $$What is its molecular formula?

Accepted Answer

$$C_4H_8$$

Question 15

Which of the following best describes the trend in ionization energy as you move down a group in the periodic table?

Accepted Answer

Ionization energy decreases.

Question 16

If $$24.0\ g of$$ $$Na_2SO_4 is $$dissolved in water, how many moles of $$Na_2SO_4$$ are present? ($$M_{Na_2SO_4} = 142.0\ g/mol)$$

Accepted Answer

$$0.17$$ moles

Question 17

Which of the following is the correct Lewis structure for $$NH_3$$?

Accepted Answer

Nitrogen with three single bonds to hydrogen and one lone pair

Question 18

A compound contains $$27.3\%$$ carbon, $$72.7\%$$ oxygen by mass. What is its empirical formula?

Accepted Answer

$$CO_2$$

Question 19

Which of the following best explains why fluorine has a higher electronegativity than lithium?

Accepted Answer

Fluorine has a higher nuclear charge and smaller atomic radius.

Question 20

How many grams of oxygen are present in $$50.0\ g of$$ $$H_2O$$? ($$M_{H_2O} = 18.0\ g/mol)$$

Accepted Answer

$$27.8\ g$$

General Chemistry Study Guide: Atomic Structure, Periodic Table, and Chemical Compounds

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