According to its periodic table entry, how many electrons does nitrogen have in its valence level?

Which of the following is a testable hypothesis? a. if i brush my teeth, i will get fewer cavities than if i don't brush my teeth. b. green toothpaste tastes better than blue toothpaste or red toothpaste. c. smart, careful, healthy people always brush their teeth. d. it's wrong to not brush your teeth before you have an important conversation with someone.

Explanation for basic character?

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?