Question 1

Which of the following ions is expected to have the largest atomic radius?

$$Ca^{2+}$$, $$S^{2-}$$, $$Cl^-$$, $$K^+$$

Accepted Answer

$$S^{2-}$$

Question 2

What is the correct ground-state electron configuration for the $$Fe^{2+}$$ ion?

Accepted Answer

$$[Ar] 3d^6$

Question 3

A student heats a sample of $$BaCl_2$$ \cdot xH_2O$$ but does not heat it to a constant mass. How will this affect the calculated value of x$?

Accepted Answer

The calculated value of $$x$$ will be too low.

Question 4

A $$10.0\ 	ext{g}$$ mixture of $$CaCO_3$$ and an inert impurity is heated, losing $$2.20\ 	ext{g} as$$ $$CO_2. $$What is the mass percentage of $$CaCO_3 in $$the original mixture? ($$CO_2 = 44.0$$\ 	ext{g/mol}$$, $$CaCO_3$$ = 100.1\ 	ext{g/mol})$$

Accepted Answer

$$50.0\%$$

Question 5

According to Coulomb's Law, which compound has the highest lattice energy?

$$NaCl$$, $$CaO$$, $$KCl$$, $$MgO$$

Accepted Answer

$$MgO$$

Question 6

If a student loses some solid $$MgCl_2 by $$spattering during a hydrate heating experiment, how will this affect the calculated mass of water lost?

Accepted Answer

The calculated mass of water lost will be too high.

Question 7

Which peak would be missing from the PES spectrum of $$Mg^{2+}$$ compared to neutral $$Mg$$?

Accepted Answer

The $$3s^2$$ peak

Question 8

What happens to the binding energy of the $$1s$$, $$2s$$, and $$2p$$ electrons when $$Mg is $$converted to $$Mg^{2+}$$?

Accepted Answer

Binding energy increases because the same number of protons pull on fewer electrons.

Question 9

How does the binding energy of the $$2p$$ electrons in $$Na^+$$ compare to that in $$Ne$$?

Accepted Answer

$$Na^+$$ has a higher binding energy because it has more protons.

Question 10

Which of the following best explains why atomic radius decreases across a period?

Accepted Answer

The effective nuclear charge ($$Z_{eff}) $$increases, pulling electrons closer.

Question 11

Which of the following statements about ionization energy is correct?

Accepted Answer

Ionization energy increases across a period due to increasing $$Z_{eff}.$$

Question 12

Which of the following ions is smallest in an isoelectronic series: $$O^{2-}$$, $$F^-$$, $$Na^+$$, $$Mg^{2+}$$?

Accepted Answer

$$Mg^{2+}$$

Question 13

Which of the following best describes why $$MgO$$ has a higher lattice energy than $$NaCl$$?

Accepted Answer

$$MgO$$ has smaller ions and higher charges.

Question 14

A mass spectrum of an unknown element shows two peaks at masses 62 and 64 with relative abundances of 70% and 30%. What is the average atomic mass?

Accepted Answer

$$63.0$$

Question 15

Which of the following best explains why the $$3d$$ electrons are not lost first when forming $$Fe^{2+}$$?

Accepted Answer

The $$4s$$ electrons are in a higher principal energy level and are lost first.

Question 16

Which of the following is true about the empirical formula?

Accepted Answer

It shows the simplest whole-number ratio of atoms.

Question 17

Which of the following best describes the trend in metallic character across a period?

Accepted Answer

Metallic character decreases across a period.

Question 18

If a hydrate is under-heated in a lab, what is the most likely error in the calculated value of $$x in$$ $$Salt \cdot xH_2O$$?

Accepted Answer

The calculated $$x$$ will be too low.

Question 19

Which of the following best explains why the atomic radius increases down a group?

Accepted Answer

More energy levels are added, increasing the distance from the nucleus.

AP Chemistry Review: Atomic Structure, Periodic Trends, and Lab Analysis

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