Which of these statements is not true? A)Atoms of the same element can have different masses
B)The nucleus of an atom has a positive charge
C)Atoms of isotopes of an element have different numbers of protons
D)Atoms are mostly empty space

C

Explanation:

should be different numbers of neutrons

the child will have heterozygous dominant chromosomes as characters of his father are dominant over the characters of his mother.

the child is heterozygous

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.