Midterm 1

matter

something that has mass and takes up space

periodic trends - reactivity

increases top to bottom for metals
increases bottom to top for nonmetals

periodic trends - mass

increases left to right and top to bottom

periodic trends - radius

increases right to left and top to bottom

periodic trends - hardness

increases bottom to top (metals)

What does every element have a unique # of?

protons

isotopes

unique # of neutrons

(ex: There’s 3He, 4He, 5He, they all have the same # of protons but diff # of neutrons)

average atomic mass =

weighted avg of isotope masses

ions

unequal # of protons & electrons

cation

# protons > # electrons

+ charge overall

anion

# protons < # electrons

- charge overall

periodic trends - shells

# of shells increases as you go down & stays the same across

How many e- does 1st shell hold

2

How many e- does 2nd shell hold

8

How many e- does the 3rd hold

18 but 8 max

coloumbs law

F = k (q1 q2) / r²

F = force
q1 q2 = charges
r² = distance between charges

what do opposite charges do?

they attract

bigger charges = stronger/weaker force
bigger distance = stronger/weaker force

= stronger force
= weaker force

Z_eff

Total Protons - Core Electrons

Greater Zeff means what

Stronger attraction

Periodic trends - valence e-

increases left to right same down a column

metallic bonding

between metals
sea of electrons

molecular covalent bonding

nonmetals

ionic bonding

metal + nonmetal

extended covalent bonding

nonmetals

solubility of metallic

doesn’t dissolve

solubility of molecular covalent

many dissolve

solubility of ionic

many dissolve

solubility of extended covalent

does not dissolve

conductivity of metallic

conducts dry

conductivity of molecular covalent

does not conduct

conductivity of extended covalent

does not conduct

conductivity of ionic

solution conducts (so when it’s dissolved in water)

metallic “hardness”

bendable, malleable

molecular covalent “hardness”

gasses, liquids, or soft solids

ionic “hardness”

hard, but brittle

extended covalent “hardness”

rigid, difficult to break

isomers

same molecular formula, different structural formula

have different skeleton connectivity

resonance structures

same atom locations, different e- locations

have SAME skeleton connectivity differ by bp or 1p e- placements

rigid container

volume doesn’t change

flexible container

volume does change

KE =

3/2 RT or ½ mV²

Flexible Containers will change V until…

Poutside = Pinside

Real Gas Law

a = attractions
b = bigness

Formal Charge

# of valence e when alone - # nonbonding e - # bonds

VSEPR - 2 Domains Electron Geometry

Linear

180*

VSEPR - 3 Domains Electron Geometry

Trigonal Planar

120*

VSEPR - 3 Domains Molecular Geometry

3 bond pairs 0 lone pairs

Trigonal Planar

VSEPR - 3 Domains Molecular Geometry

2 bond pairs 1 lone pairs

Bent

VSEPR - 3 Domains Electron Geometry

Tetrahedral

109.5*

VSEPR - 4 Domains Molecular Geometry

4 bond pairs 0 lone pairs

Tetrahedral

VSEPR - 4 Domains Molecular Geometry

3 bond pairs 1 lone pairs

Trigonal Pyramid

VSEPR - 4 Domains Molecular Geometry

2 bond pairs 2 lone pairs

Bent

Nonpolar Covalent

equal sharing

Polar covalent

unequal sharing

Ionic

Electron transferred

which property causes elements to vary in how strongly they pull on electrons

electronegativity

electronegativity

intrinsic ability of an atom to attract a bonding pair of e towards itself