Question

Beryllium (Be) has an atomic number of 4 and an atomic mass of 9. Beryllium has _____.

4 electrons
5 electrons
9 electrons
13 electrons

Answer 1

atomic number is how many protons; and as a consequence, also the number of electrons to be electrically stable i think

Answer 2

id have to google to be sure :)

Answer 3

so what would it be?

Answer 4

"In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element. In an atom of neutral charge, the atomic number is also equal to the number of electrons." - wikipedia

Answer 5

So it would be 13, right?

Answer 6

Sorry I just wanna make sure

Answer 7

4 protons, 4 electrons.

Answer 8

Amistre is correct. When you are given the atomic number, you know right away that you have that many protons. Then if it is an atom, you know it is electrically neutral and then you have to have as many electrons. So if the atomic number is 4, the number of protons is 4 and for an atom, the number of electrons is also 4.

Answer 9

Does the number of protons mirror the electrons or is that just a coincidence?

Answer 10

atoms that are electrically neutral have equal numbers of protons and electrons; they balance out.

when an atom has more of either, they become an ion and develop a positive or negative charge.

Answer 11

Okay that helps.