Because valence electrons are so important, chemists draw models showing the valence electrons of an element: electron dot structures.
Watch 0:24 - 1:10 of video
now you practice with beads!
Add these notes to your journal:
electron dot structure - 1) draw the chemical symbol 2) draw 1 dot for each valence electron (don't pair up until every side has 1)
The unpaired dots show how many bonds an atom may form.
One kind of bond is the ionic bond:
now write these notes:
An IONIC BOND involves a TRANSFER of electrons from one atom to another, turning them both into ions (charged particles).
- 2 oppositely-charged ions electrostatically attracted (like magnets)
- between a METAL and a NONMETAL. This is because metals have low electronegativity and nonmetals have high electronegativity. [The nonmetals attracts the metal's electron so strongly that yanks it away...a transfer].
Stop video at 4:38
A covalent bond involves the SHARING of electrons so each atom gets an octet
- between 2 NONMETALS [because nonmetals have high electronegativities so both attract the electrons too strongly to transfer...they just share instead]
single bond - 1 pair of shared electrons (a "bonding pair")
double bond - 2 pairs of shared electrons (2 "bonding pairs")
complete an exit ticket for electron dot structures