If an element has an atomic number of 15, then
A) the atomic mass must also be 15.
B) the atom has 15 electrons.
C) there are 7 electrons in the outermost shell.
D) the atom has 15 neutrons.
E) the atom must have only one orbital.

Question

Quizplus · Accepted Answer

The atomic number of an element is equal to the number of protons in the nucleus, which also equals the number of electrons in a neutral atom. Therefore, if an element has an atomic number of 15, it has 15 electrons. The atomic mass may vary, as it includes the number of protons and neutrons in the nucleus. The number of electrons in the outermost shell, or valence electrons, depends on the element's position on the periodic table. The number of neutrons in the nucleus can vary for different isotopes of the same element. The number of orbitals also depends on the element's electron configuration.

If an Element Has an Atomic Number of 15, Then