Chapter 3.2 Notes Flashcards
How many electrons are considered a full set
8
How do u determine the number of balance electrons for group numbers 1-2
The group number= number of valence electrons
How do u determine the number of balance electrons for group numbers 13-18
The second number(ex: group 15 has 5 valence electrons)
How do u determine the number of balance electrons for group numbers 2-12
Rebels; they don’t follow a general rule
How many electrons do the the 1st,2nd, and 3rd levels hold
1st: 2
2nd: 8
3rd: 18
Where do u look when determine the number of valence electrons
Group
Where do u look when determining the number of energy levels
Period
All elements on a period have the same number of
Rings
Why does helium, with only 2 valence electrons grouped with noble gases
It’s outermost she’ll is completely full making it nonreactive
Are group one and two very reactive
Yesssss!!!!
Group 1:Alkali metals
Soft-can be cut with knife, very low density
Alkali metal+water=
Hydrogen gas
Group 2: Alkaline-earth metals
Not as reactive as group 1 metals, more stable
Group 3-12: transition metals
Less likely to lose valence electrons, more stable elements
Lanthanides
Shiny, reactive, used in steel making
Actinides
Unstable and radioactive
Elements after 94 aren’t found in nature
Group 13-16 are
Metalloids
Group 13: boron
Aluminum
Group 14:carbon group
Nonmetals, metalloids
Group 15: nitrogen group
Gas at room temperature, 78% of the air in our atmosphere
Group 16: oxygen group
Very reactive, 21% of our air, necessary for burning to take place
Group 17-18 are
Nonmetals
Group 17:Halogens
Very reactive, never found uncombined
Group 18: noble gases
Unreactive nonmetals cause they have a full set of 8 valence electrons
Atomic mass
Average of isotopes( decimals)
Isotope
Element with different number of neutrons. Different mass cause u change the number of neutrons
Ion
Atom with a charge( change electrons)
Group
Up and down( tell us the number of valence electrons and properties)
Period
Side to side (valence electrons are: what ring. Ex: 5th period, on 5th ring)
