Help me out with electron configuration. :[

[TheLegend]

Homework Statement

What is the atomic number if the electron config is 1s2, 2s2, 2p6, 3s2, 3p4.

Homework Equations

How do I solve for electron configurations using a periodic table?

The Attempt at a Solution

I don't really have any, I am studying for a mid-term and this is all stuff I barely understood in the beginning of the year, and... well... Time makes fools of us all.

I'm not asking for a direct answer, in fact, I don't want that. I want to figure out what I'm missing (in terms of information) on how to tell the electron configuration based on either the electron configuration itself --> element or vice-versa.

Any help is very much appreciated. :)

 

[rocomath]

1s^2

what does 1 tell you? Think orbitals.

What does s tell you? Where would you find the s group?

what does 2 tell you? Think electrons, but which electrons?

 

[TheLegend]

1s^2

what does 1 tell you? Think orbitals.

What does s tell you? Where would you find the s group?

what does 2 tell you? Think electrons, but which electrons?

I know as far as to say that 1 is the energy level, s would be the sub-shell (spdf, 1357) and the ^2 would be the number of electrons within the sub shell.

But regardless, I don't know how to use that information and look at a periodic table and say, "That is..."

 

[MichaelXY]

^2 would be the number of electrons within the sub shell.
--------------------------------------------------------
Exactly, so consider what info the atomic number gives in terms of electrons.

Lithium has an atomic number of 3, its config is 1s2 2s1, do you see the relationship?