Question 1

Which of the following statements best describes the modern periodic law?

Accepted Answer

When the elements are arranged in order of increasing atomic number, certain sets of properties recur periodically.

Question 2

Which element would you expect to have the highest effective nuclear charge ($$Z_{\mathrm{eff}}) $$for its valence electrons?

Accepted Answer

Fluorine ($$F)$$

Question 3

Which of the following atoms has the largest atomic radius?

Accepted Answer

Potassium ($$K)$$

Question 4

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

Accepted Answer

Fluoride ion ($$F^-)$$

Question 5

Which of the following elements is most likely to form a cation with a $$2+$$ charge?

Accepted Answer

Calcium ($$Ca)$$

Question 6

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

Accepted Answer

The effective nuclear charge ($$Z_{\mathrm{eff}}) $$increases, pulling electrons closer to the nucleus.

Question 7

Which of the following atoms has the highest first ionization energy?

Accepted Answer

Neon ($$Ne)$$

Question 8

Which of the following electron configurations represents a violation of Hund's Rule?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^2$$ with both 2p electrons paired in the same orbital

Question 9

Which of the following elements is a metalloid and is widely used in the microelectronics industry?

Accepted Answer

Silicon ($$Si)$$

Question 10

Which of the following statements about the alkali metals is correct?

Accepted Answer

They have one valence electron and form $$1+$$ cations.

Question 11

Which of the following best describes the trend in metallic character on the periodic table?

Accepted Answer

Metallic character increases down a group and decreases across a period from left to right.

Question 12

Which of the following elements has the most negative electron affinity?

Accepted Answer

Chlorine ($$Cl)$$

Question 13

A sample of sodium metal is stored under kerosene. What property of sodium explains this storage method?

Accepted Answer

Sodium is highly reactive with oxygen and water.

Question 14

Which of the following ions has the smallest ionic radius?

Accepted Answer

$$Al^{3+}$$

Question 15

Which of the following best explains why noble gases are generally unreactive?

Accepted Answer

They have completely filled valence shells, making them stable.

Question 16

Which of the following elements would you expect to have the lowest first ionization energy?

Accepted Answer

Potassium ($$K)$$

Question 17

Which of the following electron configurations represents the ground state of a neutral phosphorus atom?

Accepted Answer

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

Question 18

Which of the following best describes the electron configuration of the $$Fe^{2+}$$ ion?

Accepted Answer

$$[Ar]\ 3d^6$

Question 19

Which of the following elements is most likely to gain one electron to achieve a noble gas configuration?

Accepted Answer

Bromine ($$Br)$$

Question 20

Which of the following best explains why the $$3d$$ subshell fills after the $$4s$$ subshell in the electron configuration of elements?

Accepted Answer

The $$4s$$ subshell is lower in energy than the $$3d$$ subshell.

Periodic Properties and the Periodic Law: Structure and Properties of the Elements

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