Valence Electrons

Groups of Periodic Table

The number of valence electrons come from the HIGHEST s AND p orbital

Write this pattern on your periodic table.

Isoelectronic - Meaning same # of electrons

• Group 18 (Noble Gases) are known for having a full octet (8 valence electrons)

• This makes them unreactive

• All atoms want to have a full octet and will gain or lose electrons in order to be like the closest noble gas

• ​Metals typically give way their valence e^- (become more positive)

• Nonmetals will typically take more valence e^- (become more negative)
  

Groups 1,2, and 13 (first 3 main groups) give away their valence e^-

Groups 1,2, and 13 (first 3 main groups) give away their valence e^-

Group 14 (Main group) 4 will either gain or lose their valence electrons and become more positive or negative.

Group 14 (Main group) 4 will either gain or lose their valence electrons and become more positive or negative.

Groups 15,16,17 (Main Groups 5,6,7) will gain and become more negative

Groups 15,16,17 (Main Groups 5,6,7) will gain more valence electrons and become more negative

Oxidation State

• The charge on the ion once it loses its valence electrons, is called its oxidation state.

• This will become important when we start making compounds for chemical reactions.

Shows the valence electrons for atoms. Place valence electrons around the SYMBOL of the element. Fill s orbital first, then p orbitals 1 at a time

X

​s

​p

​p

​p

1. Determine number of valence electrons:

2. Write the symbol

3. Draw dots around to represent the number of valence electrons. Fill s orbital first, then 1 at a time for p orbitals

1. Determine number of valence electrons:

2. Write the symbol

3. Draw dots around to represent the number of valence electrons. Fill s orbital first, then 1 at a time for p orbitals

P

s

p

p

p

• Atoms can exist as ions (having a charge) which means their number of electrons is NOT equal to the number of protons

• We can write the electron configuration for ions, once we take into account the number of electrons an ion has

What is the electron configuration for Al⁺³