CHEM 120 Homework 3. Chapter 3

1. In the modern periodic table, the elements are arranged according to increasing ________.

a. atomic masses b. number of neutrons c. atomic number d. mass number

2. How many periods are found on the periodic table?

a. 2 b. 7 c. 18 d. 32

3. Which period contains the element Cesium?

a. 2 b. 4 c. 6 d. 7

4. Where are the alkaline earth metals located on the periodic table?

a. Group 1 (IA) b. Group 2 (IIA) c. Group 13 (IIIA) d. Group 14 (IVA) e. Group 17 (VIIA)

5. Which one of the following is not a representative element

a. Na b. As c. Ca d. Fe e. Cl

6. How many orbitals are in an s sublevel? How many in a p sublevel?

a. 2;6 b. 1;1 c. 1; 3 d. 3; 5

7. Which of the following correctly gives the electron capacity of a

principal energy level in terms of the number n?

a. n b. 2n c. 2n + 2 d. n² e. 2n²

7. What requirement must be met in order for two electrons to coexist in

the same orbital?

1. they go to a s orbital
2. they go to a p orbital
3. they must have opposite spins
4. they must have parallel spins

8. How many valence electrons are present in an atom of silicon?

a. 2 b. 3 c. 4 d. 5 e. 7

9. The electronic configuration in an atom of argon,

a. 1s²2s²

b. 1s²2s²2p⁶

c. 1s²2s²2p⁶3s²3p⁶

d. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶

10. Common valence electron configuration of halogens

a. ns¹ b. ns² c. ns² 3p² d. ns² np³ e. ns² np⁵

11. What is not isoelectronic with K⁺?

a. S^2- b. Ar c. Cl^- d. Na⁺ e. Ca²⁺

12. Which of the following atoms has the biggest size (radius)?

a. Na b. Al c. Cl d. Rb e. I

13. Which of the following elements has the highest ionization energy?

a. Li b. B c. O d. F e. Ne

14. Which one of the following elements has the highest electron affinity?

a. Li b. K c. Kr d. O e. Cl

15. What charge is found on a ion from Al?

a. +1 b. -2 c. +3 d. -3