Question

bellwork, day 3:
eview of the atomic size trend\ directions: please answer the following questions based on what we learned yesterday. 1. why does atomic size increase as you go down a group? 2. why does atomic size decrease as you go from left to right across a period? 3. circle the element in each of the following pairs with the larger atomic radius (size): a) fluorine or iodine b) germanium or selenium c) cobalt or nickel

Explanation:

1. As you go down a group, new electron - shells are added. Each new shell is farther from the nucleus, increasing the atomic size.
2. Across a period, the number of protons increases while electrons are added to the same shell. The increased nuclear charge pulls the electrons closer, decreasing atomic size.

3.

• a) Iodine is below Fluorine in the same group, so Iodine has a larger atomic radius.
• b) Germanium and Selenium are in the same period, and Germanium is to the left of Selenium. So Germanium has a larger atomic radius.
• c) Cobalt and Nickel are in the same period, and Cobalt is to the left of Nickel. So Cobalt has a larger atomic radius.

Answer:

1. New electron - shells are added as you go down a group, increasing the atomic size.
2. Increased nuclear charge pulls electrons closer across a period, decreasing atomic size.

3.
a) Iodine
b) Germanium
c) Cobalt