Question 1

Which of the following is the correct electron configuration for the element phosphorus (atomic number 15)?

Accepted Answer

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

Question 2

Which element has the abbreviated electron configuration $[Ar] 4s^2 3d^7$?

Accepted Answer

Cobalt (Co)

Question 3

What is the total number of valence electrons in a silicon (Si) atom?

Accepted Answer

4

Question 4

Which of the following elements has the largest atomic radius?

Accepted Answer

Potassium (K)

Question 5

Which of the following statements about ionization energy is correct?

Accepted Answer

Ionization energy increases across a period from left to right.

Question 6

Which element would have the following electron-dot (Lewis) symbol: $\cdot \mathrm{Cl} \cdot$ (with 7 dots around Cl)?

Accepted Answer

Chlorine

Question 7

A neutral atom of selenium (Se) has which of the following electron configurations?

Accepted Answer

$1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^4$

Question 8

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

Accepted Answer

The number of protons increases, pulling electrons closer to the nucleus.

Question 9

Which element is expected to have the highest metallic character?

Accepted Answer

Cesium (Cs)

Question 10

Which of the following is the correct orbital diagram for nitrogen (N)?

Accepted Answer

1s: $\uparrow\downarrow$ 2s: $\uparrow\downarrow$ 2p: $\uparrow$ $\uparrow$ $\uparrow$

Question 11

Which of the following elements has the greatest first ionization energy?

Accepted Answer

Fluorine (F)

Question 12

Which of the following is an exception to the expected electron configuration due to increased stability of a half-filled or filled d subshell?

Accepted Answer

Chromium (Cr)

Question 13

What is the group number and number of valence electrons for calcium (Ca)?

Accepted Answer

Group 2A (2), 2 valence electrons

Question 14

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

Accepted Answer

Metallic character increases

Question 15

Which of the following elements has the electron configuration $1s^2 2s^2 2p^4$?

Accepted Answer

Oxygen (O)

Question 16

A patient is exposed to a new element with the electron configuration $[Ne] 3s^2 3p^5$. Which group does this element belong to, and what is its likely chemical behavior?

Accepted Answer

Group 7A (17); likely to gain one electron to form a -1 ion

Question 17

Which of the following statements is true regarding the filling order of sublevels in the periodic table?

Accepted Answer

The 4s sublevel fills before the 3d sublevel.

Question 18

Which of the following best explains why the ionization energy decreases as you move down a group?

Accepted Answer

Valence electrons are farther from the nucleus and easier to remove.

Question 19

Which of the following is the correct electron configuration for copper (Cu), considering the stability of filled d subshells?

Accepted Answer

$[Ar] 4s^1 3d^{10}$

Electron Configurations and Periodic Properties – Week 3 Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards