Electronic Structure Flashcards

All 6 cards in this deck

Which shells do electrons in an atom occupy first?

The lowest available energy levels — the innermost available shells.

How many electrons fill the first, second and third shells of an atom?

2 in the first, 8 in the second, 8 in the third.

What are the steps to write the electronic structure of an atom?
e.g. sodium, atomic number 11

1. Number of electrons = atomic number = 11.
2. Fill the first shell with 2, then the second with up to 8: 2, 8 used.
3. Put the rest in the next shell: $2,8,1$.

In an electronic structure written as numbers, what does the last number tell you?
e.g. $2,8,1$

The number of electrons in the outer shell — 1 for this atom.

In what two ways can the electronic structure of an atom be represented?

By numbers separated by commas (e.g. $2,8,3$) or by a diagram of electrons in shells.

True or false? You use the mass number of an element to work out its electronic structure.

False. You use the atomic number, which equals the number of electrons in the atom.