1. The number of protons plus neutrons is the atom’s approximate ___________ .
A. atomic mass
B. atomic number
C. atomic model
D. atomic nucleus
2. Mendeleev developed the periodic table of the elements, which _______ elements.
A. alphabetizes
B. classifies
C. measures
D. weighs
4. The atoms share _____ in a covalent bond
A. proton
B. ion
C. nucleus
D. electrons
