ch.3 atomic and molecular structure

Question 1

atomic theory

Answer 1

1. all matter is composed of atoms, which are indivisible and indestructible
2. atoms of a specific element are identical in mass and properties
3. compounds are formed by whole number ratios of two or more atoms
4. a chemical reaction is a rearrangement of atoms

Question 2

atomic number

Answer 2

number of protons
above chemical symbol

Question 3

mass number

Answer 3

sum of protons and neutrons
not on periodic table

Question 4

atomic mass

Answer 4

average of isotopes
below chemical symbol

Question 5

isotopes

Answer 5

different number of neutrons

Question 6

principle quantum number

Answer 6

at n=1, an electron is closest to the nucleus

• the maximum number of electrons that a given electron shell can hold is 2n²

Question 7

azimuthal quantum number (I)

Answer 7

describes the shape of subshells or the orbital shape within each principle energy level

• I=0 is s, I=1 is p, I=2 is d, I=3 is f

Question 8

magnetic quantum number

Answer 8

describes the orientation of orbitals in space

I=1 is a p subshell, with mI values of -1, 0, and 1

Question 9

spin quantum number (m_s)

Answer 9

describes the angular momentum of an electron (denoted as either +1/2 or -1/2)

• electrons in the same orbital must have antiparallel spins

Question 10

electron configuration

Answer 10

• the first number describes the principle energy level, the letter describes the subshell, and the superscript tells you the number of electrons in that subshell

Question 11

formal charge

Answer 11

(# of valence e-) - (# of nonbonding e-) - (# of bonds)