Question

20 analyze the bohr model below. 6. which three statements best describe this bohr model? a the mass number is 4 and the atomic number is 2. b this element has a full energy level. c this element has 2 valence electrons. d the mass number is 2 and the atomic number is 4. e this element has an unfilled energy level.

Explanation:

Step1: Identify parts of Bohr - model

In the Bohr - model, the number of protons is the atomic number and the sum of protons and neutrons is the mass number. The model shows 2 protons (positively - charged particles in the nucleus) and 2 neutrons (neutral particles in the nucleus), so the atomic number is 2 and the mass number is 4. Also, there are 2 electrons in the outermost shell.

Step2: Analyze energy - level and valence - electron concepts

The first energy level can hold a maximum of 2 electrons. Since there are only 2 electrons in total and they are in the first energy level, the energy level is full and the number of valence electrons (outer - most electrons) is 2.

Answer:

A. The mass number is 4 and the atomic number is 2.
B. This element has a full energy level.
C. This element has 2 valence electrons.