1. A Review of General Chemistry

How many electrons does an atom of each of the following elements need to gain to achieve a noble gas configuration? By gaining that many electrons, which noble gas configuration is achieved?

(c) Phosphorus

Nitrogen has relatively stable isotopes (half-life greater than 1 second) of mass ­numbers 13, 14, 15, 16, and 17. All except ¹⁴N and ¹⁵N are radioactive.) Calculate how many protons and neutrons are in each of these isotopes of nitrogen.

PRACTICE: Determine which of the three principles of electron configuration is being broken in the electron diagrams below.

How many electrons does an atom of each of the following elements need to lose to achieve a noble gas configuration? By losing that many electrons, which noble gas configuration is achieved?

(d) Potassium

PRACTICE: Determine which of the three principles of electron configuration is being broken in the electron diagrams below.

How many electrons does an atom of each of the following elements need to lose to achieve a noble gas configuration? By losing that many electrons, which noble gas configuration is achieved?

(a) Beryllium

a. How many protons do the following species have?

b. How many electrons does each have?

1. Na⁺
2. Ar
3. Cl^-

Draw the ground-state electronic configuration for each of the following:

a. Mg

Chlorine has two isotopes, ³⁵Cl and ³⁷Cl; 75.77% of chlorine is ³⁵Cl, and 24.23% is ³⁷Cl. The atomic mass of ³⁵Cl is 34.969 amu, and the atomic mass of ³⁷Cl is 36.966 amu. What is the atomic mass of chlorine?

A chemistry student drew the following incorrect electron configuration for carbon. (b) Which rule wasn't followed by the student?

Bromine-79 (50.7% abundance) has an atomic mass of 78.918 amu, whereas bromine-81 (49.3% abundance) has an atomic mass of 80.916 amu. From these data, calculate the average atomic mass of bromine that you would expect to see in the periodic table.

Give the electron configuration of the following elements.

(c) O

Give the charge most likely to result from ionization of the following metals.

(c) Potassium

Write the electronic configurations of the third-row elements shown in the partial ­periodic table in Figure 1-6.

Name the element that corresponds to each electronic configuration.

a. 1s² 2s² 2p²

b. 1s² 2s² 2p⁴

c. 1s² 2s² 2p⁶ 3s² 3p³

d. 1s² 2s² 2p⁶ 3s² 3p⁵