Question

Which are period numbers for 1 to 20 elements?

Answer 1

Answer:

Terms in this set (20)

Hydrogen #1. period 1.

Helium #2. period 1, group 18.

Lithium #3. period 2, group 1.

Beryllium #4. period 2, group 2.

Boron #5. period 2, group 13.

Carbon #6. period 2, group 14.

Nitrogen #7. period 2, group 15.

Oxygen #8. period 2, group 16.

Answer 2

Answer:

Terms in this set (20)

1. Hydrogen #1. period 1.

2. Helium #2. period 1, group 18.

3. Lithium #3. period 2, group 1.

4. Beryllium #4. period 2, group 2.

5. Boron #5. period 2, group 13.

6. Carbon #6. period 2, group 14.

7. Nitrogen #7. period 2, group 15.

8. Oxygen #8. period 2, group 16.