Stability and Ionic Bonding. Section 20.1 & 20.2. SC Standards Covered. Standard PS-4.1 Explain the role of bonding in achieving chemical stability. Standard PS-2.5
Section 20.1 & 20.2
Why do Elements Form Compounds?
- the noble gases are extremely stable atoms that do not combine with other elements.
- it is the eight valence electrons that make the noble gas atoms stable
- When atoms begin to lose, share, or gain electrons they begin to get attracted to other atoms and form chemical bonds - a force that holds atoms together in a substance.
What ion will Sodium form?
Since sodium has 1 valence electron it can lose that electron and then have eight valence elect.
Superscript – written above line; gives the charge of ion
Group 1 → 1 valence e- → +1
Group 2 → 2 valence e- → +2
Group 13 → 3 valence e- → +3
What ion will fluorine form? begin to get attracted to other atoms and form
Fluorine needs to gain 1e- in order to become stable
- This will give fluorine a -1 charge
Group 17 → 7 valence e-→ -1
Group 16 → 6 valence e- → -2
Group 15 → 5 valence e- → -3
Explain the formation of the ionic bond between sodium and chlorine
Na+[ Cl ]-1
Electron dot struct.
Steps to draw electron dot structures for ionic compounds begin to get attracted to other atoms and form
5. Write out the chemical formula using subscripts to show how many of each element it took
Lets try aluminum and oxygen!! how many of each element it took
[ O ]-2
Use electron dot structures to write chemical formulas for the following combination of elements: