quiz-mystery

1. The symbol of the element in the third period with 5 valence electrons and is used in the manufacture of safety matches.

• A. POTASSIUM

• B. OXYGEN

• C. PHOSPHOROUS

2. The symbol of the element in the first period with 2 valence electrons and used to inflate party balloons.

• A. OXYGEN

• B. HELIUM

• C. HYDROGEN

3. The symbols of the two gaseous elements in the second period with valence electrons equal to 5 and 6, respectively.

• A) N, O

• B) O, F

• C) B, N

4. The first letter of the name of the principle which states that electrons fill atomic orbitals of the lowest available energy levels first before occupying higher levels in the atom’s ground state.

• A) A

• B) P

• C) H

5. The symbol of the halogen with a complete electron configuration:1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p5.

• A) I

• B) Cl

• C) F