The Mighty Electron

Electrons in Energy Levels exist in one or more energy levels surrounding the nucleus

Energy levels 1st energy level holds up to 2 e- 2nd energy level holds up to 8 e- 3rd energy level holds up to up to 18 e- Valence electrons- number of electrons in outer level- this determines the chemical reactivity of the element! -Elements in the same family have similar chemical reactivities bc they have the same # of valence e-

Valence Electrons Valence electrons are organized according to vertical groups/families in the Periodic Table 8 1 2 3 4 5 6 7

Bohr Atomic Model Shows the # of p+ and n0 in the nucleus and e- in energy levels Which element is shown?

Lewis Dot Structure Shows the number of valence (outer) electrons Na

Octet Rule (does not apply to 1st energy level) All elements are happy when they have 8 outer electrons (full outer shells) Ex. Aluminum (Al) has 13 protons, 14 neutrons and 13 electrons. There are 3 valence electrons in Al Al gives up those 3 electrons to be happy; this creates 10 electrons and 13 protons; Al has a +3 charge

Elements with 1, 2 or 3 outer electrons tend to “lose” or transfer their extra electrons to other elements when they bond together 8 1 2 3 4 5 6 7

Elements with 5, 6, or 7 outer electrons tend to gain electrons when they bond with other elements. 8 1 2 3 4 5 6 7

Elements with 4 valence electrons may gain or lose electrons when bonding 8 1 2 3 4 5 6 7

Ion Ion- an atom that has gained or lost electrons; has an overall charge Let’s look at Sodium (Na) 11p+ 11p+ 11e- loses 1 e- 10e- becomes an ion Na 1+

What ions do the following elements form? Be O F Rb Ar Be+2 O-2 F-1 Rb+1 None