Electron configuration S

The electron configuration of an atom is 1s²2s²2p⁶.  The number of electrons in the atom is 

An orbital can at most hold how many electrons?

Which of the following statements regarding electronic orbitals is/are correct?

What atom matches this electron configuration? 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰

What electron configuration matches an oxygen atom?

The electron configuration of an atom is 1s²2s²2p⁶.  The number of valence electrons in the atom is 

What is the electron configuration for this atom?

How many electrons does Si contain? (click to see image)

How many valence electrons does Si contain? (click to see image)