Question 1

Which statement about ions is correct?

Accepted Answer

Ions have unequal numbers of protons and electrons.

Question 2

Which of the following statements is TRUE regarding protons and neutrons?

Accepted Answer

Protons and neutrons have approximately the same mass.

Question 3

Which element is a halogen?

Accepted Answer

Cl

Question 4

How many protons, neutrons, and electrons are present in $$^{24}\mathrm{Mg}$$?

Accepted Answer

12 protons, 12 neutrons, 12 electrons

Question 5

Which pair of cobalt atoms are isotopes?

Accepted Answer

$$^{59}\mathrm{Co}$$ and $$^{58}\mathrm{Co}$$

Question 6

What is the atomic symbol for an atom with 27 protons and 31 neutrons?

Accepted Answer

$$^{58}_{27}\mathrm{Co}$$

Question 7

Calculate the average atomic mass of lithium given the following isotopic abundances and masses: 7.30% $$6.017$$ amu, 92.70% $$7.018$$ amu.

Accepted Answer

$$6.94$$ amu

Question 8

Write the nuclear equation for the alpha decay of $$^{227}\mathrm{Th}$$ accompanied by gamma ray emission.

Accepted Answer

$$^{227}_{90}\mathrm{Th} \$$rightarrow ^{223}$$_{88}\mathrm{Ra} $$+ ^{4}$$_{2}\mathrm{He} + \gamma$$

Question 9

A 68 mg sample of a radioactive compound has a half-life of 12 hours. How much remains after 2 days?

Accepted Answer

4.25 mg

Question 10

Assign the oxidation states for each element in $$\mathrm{CrO}_4$$^{2-}$$.

Accepted Answer

Cr: +6, O: -2

Question 11

In the reaction $$\mathrm{C}_2\mathrm{H}_4 + \mathrm{Cl}_2 \rightarrow \mathrm{C}_2\mathrm{H}_4\mathrm{Cl}_2$$, which element is oxidized?

Accepted Answer

Cl$$_2 is $$reduced, C$$_2H$_4 is $$oxidized

Question 12

Balance the following redox reaction using the half-reaction method: $$\mathrm{Al} + \mathrm{Ag}^+ \rightarrow \mathrm{Al}^{3+} + \mathrm{Ag}.$$

Accepted Answer

$$\mathrm{Al} + 3\mathrm{Ag}^+ \rightarrow \mathrm{Al}^{3+} + 3\mathrm{Ag}$$

Question 13

Which compound is ionic and what is its name: $$\mathrm{FeCl}_3$$?

Accepted Answer

Ionic, Iron(III) chloride

Question 14

Which compound is covalent and what is its name: $$\mathrm{NO}_2$$?

Accepted Answer

Covalent, Nitrogen dioxide

Question 15

What is the oxidation state of nitrogen in $$\mathrm{N}_2\mathrm{O}$$?

Accepted Answer

N: +1

Question 16

Which element is a noble gas?

Accepted Answer

Ar

Question 17

Which element is an alkali metal?

Accepted Answer

Rb

Question 18

Which element is a transition metal?

Accepted Answer

Zr

Question 19

Which compound is ionic and what is its name: $$\mathrm{Na}_2\mathrm{CO}_3$$?

Accepted Answer

Ionic, Sodium carbonate

Unit 2 General Chemistry Review – Step-by-Step Study Guidance

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