unit 2 test review NOTES

nuclear notation

nuclear notation

A = mass, biggest number on top

Z = atomic #, under mass

X = name

C = charge, like an exponent

how to find atomic #?

number of protons (+) or atomic name in periodic table

how to find mass?

protons + neutrons

how to find # of neutrons?

mass - atomic #

E ↑ f ↑ λ ↓

n = 1, 2, 3..

ℓ = 0 to (n-1)

m_ℓ = -ℓ to ℓ

m_s = ± 1/2

how to find avg mass?

add percents * mass number and divide by 100

turn percents > decimal then multiply by mass numbers

how to find percent composition of each isotope?

x + y = 1

1: replace w/ the avg mass

y = 1 - x

new: x + (1-x) = 1

isolate x

y = 1 - x

then turn percentage

subtract from 100 to get x’s percentage

paramagnetism

unpaired electrons

attracted by magnetic field

diamagnetism

paired e^-

not affected by magnetic field

electronegativity trend

how well an element can attract electrons

halogens are the most electronegative because they have 7 valence electrons; noble gases are not electronegative

ions atomic radius

ion: element w/ a charge

largest to smallest: anions (-) » neutral » cations (+)

increases down a column

atomic radii

½ distance between nuclei

closest to Cs, Fr, Rn has higher atomic radii

valence electrons trends

ionic charge trends

first ionization energy trends

how to find energy

E = BE + KE

E = hc/λ