Question 1

Which of the following is the correct electron configuration for the element chlorine (Cl), atomic number 17?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^6$$ $$3s^2$$ $$3p^5$$

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 best explains why ionization energy increases across a period from left to right?

Accepted Answer

The number of protons increases, strengthening the attraction between the nucleus and valence electrons.

Question 6

Which of the following is the correct orbital diagram for nitrogen (N), atomic number 7?

Accepted Answer

Two boxes with paired arrows for $$1s$$ and $$2s$$, and three separate boxes with single arrows (all up) for $$2p$$

Question 7

Which of the following elements is most likely to have a high metallic character?

Accepted Answer

Cesium (Cs)

Question 8

What is the electron configuration for a neutral atom of selenium (Se), atomic number 34?

Accepted Answer

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

Question 9

Which of the following best describes the trend in atomic size for representative elements as you move down a group in the periodic table?

Accepted Answer

Atomic size increases due to the addition of energy levels.

Question 10

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

Accepted Answer

Fluorine (F)

Question 11

A patient is found to have a deficiency in magnesium. Which of the following is the correct electron-dot (Lewis) symbol for magnesium (Mg)?

Accepted Answer

Mg with two single dots on opposite sides

Question 12

Which of the following electron configurations represents an atom with 5 valence electrons in the third energy level?

Accepted Answer

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

Question 13

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): $$[Ar] 4s^1$ 3d^5$

Question 14

Which of the following statements about valence electrons is correct for representative elements?

Accepted Answer

The group number equals the number of valence electrons.

Question 15

A neutral atom of calcium (Ca) is in Group 2A (2), Period 4. What is its valence electron configuration?

Accepted Answer

$$4s^2$$

Question 16

Which of the following best describes the trend in metallic character across a period from left to right?

Accepted Answer

Metallic character decreases.

Question 17

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

Accepted Answer

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

Question 18

Which of the following elements is in Group 5A (15) and has the electron configuration $$1s^2$$ $$2s^2$$ $$2p^3$$?

Accepted Answer

Nitrogen (N)

Question 19

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

Accepted Answer

The increasing number of protons pulls electrons closer to the nucleus.

Electron Configurations and Periodic Properties: Week 3 Study Notes

스터디 가이드 - 연습 문제