Question

the tolal number of protons and neutrons in an atom​

Answer 1

Answer:

Its nucleus also contains two neutrons. Since 2+2=4, we know that the mass number of the helium atom is 4. Finally, the helium atom also contains two electrons, since the number of electrons must equal the number of protons.

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Mass Number.

Name beryllium

Symbol Be

Protons 4

Neutrons 5

Electrons

Answer 2

is called atomic number ...dont know