An element has an atomic number of 78. The number of protons and electrons in a neutral atom of the element are

A) 78 protons and 0 electrons.

B) 78 protons and 39 electrons.

C) 156 protons and 78 electrons.

D) 39 protons and 39 electrons.

E) 78 protons and 78 electrons.


Answer: E

The number of protons an element has is called the atomic number. In a neutral atom, there are the same number of protons and electrons.

Biology - Biology 160 - 1 to 4