Which of the following statements are true for the symbol given directly below ?

Question

64
Zn2+
30





a) The ion represented by the symbol has 32 electrons

b) The ion represented by the symbol has 94 protons

c) The ion represented by the symbol has 30 neutrons

d) The ion represented by the symbol has a total of 64 protons and neutrons

e) The ion represented by the symbol has an atomic number of 30

Answer 1

Both "D" and "E" are correct.

The top number is the mass number for that ion. The mass is the total number of protons + neutrons in the nucleus.

The bottom number is the number of protons only in the nucleus. By definition, the number of protons in the nucleus is the atomic number.

"A" cannot be true. If the ion had 32 electrons and only 30 protons it would have a charge of 2- instead of 2+

"B" cannot be true. The mass is the top number which is 64.

"C" cannot be true. The number of neutrons is found by subtracting the atomic number (30) from the mass number (64) so there would be 34 neutrons.

Answer 2

a is false, as the Zn2+ ion will have 28 electrons, not 32.
b is false, as Zn will have 30 protons no matter what isotope or ion it forms.
c is false, as Zn-64 will have 34 neutrons, not 30.
d is true, as 64 is the atomic mass, which is the sum of the number of protons and neutrons.
e is also true, as all isotopes and ions of zinc will have 30 protons, which is the atomic number.

Answer 3

a,d,e