Chem1090 Test#1

118

28

• - groups 1, 2, 13-18 are the "A" team
• - representative elements
• - main group elements

• - groups 3-12
• - "B" group

28 elements at the bottom of the periodic table

7

18

• - metals
• - nonmetals
• - metalloids

• F=C(1.8)+32
• C=(F-32)/1.8
• K=C+273.15

• -7 total units
• - we typically only use 5

the number of the element itself

the atomic mass

ex. He (Helium) atomic mass is 4.003

atoms that have the same atomic number but different mass number

Subtract the number of protons from the isotope number to get the number of neutrons.

the mass of an atom (AMU)

Example - Isotopes 12C and 13C with AMU's 12.00000 and 13.003355 and natural abundance % of 98.93 and 1.07

Average mass (C)= (0.9893)(12.00000amu)+(0.0107)(13.003355amu) = 12.01 amu

represents the average mass of the naturally occurring mixture of isotopes

• -% mass of an element= n(atomic mass of element)/molecular or formula mass of compound
• - the multiply answer by 100%

• example: molecular mass of ibuprofen C13H18O2
• 13(12.01amu)+18(1.008amu)+2(16.00amu) = 206.27

D=M/V or D=g/ml