What is the correct electron configuration of the element with atomic number 20?

Answer 1

1s 2 2s 2 2p6 3s2 3p6 4s2

or

Ar 4s2 (Noble gas form)

In noble gas form, you go back to the noble gas (the last group on the Periodic Table) prior to the element you are writing the configuration for. The electron configuration is the same up until that point. Then you write down the difference.

In this example, the electron configuration for Argon (Ar) is 1s2 2s2 2p6 3s2 3p6. If you fill up the shells until 4s2, you get calcium. It's faster to abbreviate by saying "Ar 4s2"

Answer 2

1s 2 2s 2 2p6 3s2 3p6 4s2

or

Ar 4s2 (Noble gas form)

In noble gas form, you go back to the noble gas (the last group on the Periodic Table) prior to the element you are writing the configuration for. The electron configuration is the same up until that point. Then you write down the difference.

In this example, the electron configuration for Argon (Ar) is 1s2 2s2 2p6 3s2 3p6. If you fill up the shells until 4s2, you get calcium. It's faster to abbreviate by saying "Ar 4s2"

Answer 3

The element with 20 electrons is calcium and it has an electron shell configuration of: 2.8.10; the electron shell configuration is simple to work out, all you have to do is remember these:

• 1st electron shell can hold 2 electrons;
• 2nd electron shell can hold 8 electrons;
• 3rd electron shell can hold 18 electrons;
• 4th electron shell can hold 32 electrons.

Answer 4

because the number of protons always equal the number of electrons and calcium has 20 protons

Answer 5

2:8:8:2....that mus be calcium

Answer 6

calcium

Answer 7

226262

1s2s2p3s3p4s