Explanation:
no.A (He) I think.............
Answer:
Rb: [Kr] 5s
Step-by-step explanation:
Rb is element 37, the first element in Period 5.
It has one valence electron, so its valence electron configuration is 5s.
The noble gas configuration uses the symbol of the previous noble gas as a shortcut for the electron configurations of the inner electrons.
The preceding noble gas is Kr, so the electron configuration is Rb: [Kr] 5s.
Answer:
Protons and neutrons
Explanation:
The particles to forms the nucleus of an atom are the protons and neutrons of the atoms.
These materials are located in the tiny nucleus and contributes the most mass of the atom.
- Protons are the positively charged particles in an atom
- Neutrons do not carry any charges.
- Sum of the protons and neutrons gives the mass number of the atom.