## What are the number of elctrons around the central atoms?

**Anonymous**

Draw the best Lewis structure for each molecule. Then select the number of electrons around the central atom from the list; the choices are 2, 4, 6, 8, 10, 12, or 14 electrons.

XeO2F2

HNO3

H3PO4

ClO41−

H2SO4

BCl3

I just need to know the total number of electrons around the central atoms.

Martin17 (not verified)| 5 September 2008 - 3:29am## The total number of

The total number of electrons around a neutral atom equals its atomic number; these are filled according to the quantum numbers. Oxygen is 8 so there are 8 electrons; 2 completely fill the 1s level; another 2 completely fill the 2s sublevel; the remaining 4 partially fill the 2p sublevel, leaving space for another 2 electrons if they can find a positive charge to balance them out. H (atomic number 1) just happens to have such an electron and needs another electron to fill its 1s level, so if O can find 2 wandering H's it can negotiate joint custody and both parties will be happy; hence H:O:H or H

_{2}O. Carbon is 6 so it completely fills the 1s and 2s levels, with 2 in the 2p awaiting 4 more, so it can negotitate any number of arrangements, which makes life enjoyable. It can get those 4 lectrons by sharing 2 each from a friendly O atom (hence CO_{2}, hence O:C:O or loaning 1 each to four Cl atoms who are only 1 short of filling their 3p sublevels to be content, hence----------------------Cl

----------------------..

-------------------Cl:C:Cl or CCl

_{4}.----------------------..

----------------------Cl

Neon is 10 so it completely fills 2 in the 1s level, 2 in the 2s sublevel and the remaining 6 will completely fill the 2p level making Ne disinclined to look for any more electrons; hence it is monatomic and a noble gas.