Question 1

Which of the following best describes the difference between a physical change and a chemical change?

Accepted Answer

A physical change does not alter the chemical composition of a substance, while a chemical change results in the formation of new substances.

Question 2

Which of the following is a mixture?

Accepted Answer

Air

Question 3

How many significant figures are in the measurement 0.00450 kg?

Accepted Answer

3

Question 4

Which group on the periodic table contains the noble gases?

Accepted Answer

Group 18

Question 5

What is the mass number of an atom with 20 protons, 22 neutrons, and 20 electrons?

Accepted Answer

$$42$$

Question 6

Which of the following ions is a polyatomic ion?

Accepted Answer

$$\mathrm{SO_4$^{2-}}$$

Question 7

Which element has the highest electronegativity according to the periodic table provided?

Accepted Answer

Fluorine

Question 8

What is the electron configuration for a neutral atom of nitrogen ($$\mathrm{N}$$, atomic number 7)?

Accepted Answer

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

Question 9

Which of the following compounds will form hydrogen bonds?

Accepted Answer

Ammonia ($$\mathrm{NH_3$})$$

Question 10

Convert 2500 grams to kilograms using the conversion factor $$1\ \mathrm{kg} = 1000\ \mathrm{g}.$$

Accepted Answer

$$2.5\ \mathrm{kg}$$

Question 11

Which of the following molecules has a trigonal planar geometry?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 12

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 13

Which of the following is the correct formula for the sulfate ion?

Accepted Answer

$$\mathrm{SO_4$^{2-}}$$

Question 14

Which of the following elements is most likely to form a diatomic molecule in its natural state?

Accepted Answer

Oxygen

Question 15

Which of the following compounds is ionic?

Accepted Answer

Sodium chloride ($$\mathrm{NaCl})$$

Question 16

What is the charge on the phosphate ion?

Accepted Answer

$$-3$$

Question 17

Which of the following best describes the trend in electronegativity across a period in the periodic table?

Accepted Answer

Electronegativity increases from left to right.

Question 18

Which of the following molecules has a bent molecular geometry?

Accepted Answer

$$\mathrm{H_2O}$$

Question 19

Which of the following best describes a covalent bond?

Accepted Answer

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

Question 20

A compound has an electronegativity difference of 2.0 between its atoms. What type of bond does it most likely have?

Accepted Answer

Covalent polar

GOB Chemistry Exam 1 Study Guide: Elements, Atomic Structure, Bonding, and Molecular Geometry

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