Ch 1
List 2 PHYSICAL properties:
color, density, mass, temperature, etc.
How many neutrons does 14C have?
8. 14 is the mass number (n + p). Carbon has 6 p, so n = 8.
Which light has the LONGEST wavelength?
red, blue, UV, IR, yellow
IR - lowest energy = longest wavlength
What is the valence-shell electron configuration of a halogen atom in Period 3?
[Ne] 3s2 3p5
Which has the higher lattice energy? LiF, NaCl, or CaO?
CaO - becuase +2/-2 and charge matters over size for strength of attraction in lattice energy.
How to report with correct sig figs?
11.577 mL + 7.80 mL =
19.38 mL
report to least precise place.
List a group 13 element from the 5th period:
In
group = column; period = row
What is the frequency of IR light with a wavelength of 0.23 mm?
1.34E12 Hz
c = lambda * v => v = c/lambda
3e8 m/s / 0.23E-3 m = 1.34E12 s-1
Which atom in the 2p block has the smallest effective nuclear charge, Zeff?
Boron.
Zeff = Z − inner core e-. BZeff = 5 – 2 = +3; FZeff = 9 – 2 = +7. Zeff increases across a period.
What formula is strontium fluoride?
SrF2
A substance has the following properties: Melting point: -32.6ºC; Boiling point: -10.5ºC
What phase is the substance at -5.4ºC?
gas
How many electrons in 128Te2-?
52+2 = 54 electrons
What is the energy of 423 nm light from Cs metal?
4.70E-19J
E = hc/lambda
Which monatomic ion of charge +1 has the electron configuration: [Ar] 3d10 4s2?
Ga+ (Z = 31)
An ion of +1 charge means its atom lost 1 e-. Gallium (neutral) is: [Ar] 3d10 4s2 4p1. Removing 1 e- leaves Ga+ with: [Ar] 3d10 4s2
What is the name of: NH4OH?
Ammonium hydroxide
An airplane flies at 632. km/h. How far does it travel in 3.0 min?
32. km
2 sig figs!
What is avg atomic mass of Cu?
69.17% 62.929599 amu; 30.83% 64.927793 amu
63.55 amu -
average atomic mass = % * mass + % * mass, etc.
Which electronic transition shown is an emission with the shortest wavelength?
A. n = 4 to n = 3; B. n = 1 to n = 2; C. n = 1 to n = 6; D. n = 4 to n = 2
D. only A & D are emissions. largest energy gap = shortest wavelength.
Arrange the elements Mg, Cl, P, Rb in order of increasing IE1.
Rb < Mg < P < Cl
What is the name of CuBr2?
copper(II) bromide
What volume is occupied by an object with density of 1.78 g/cm3 and mass of 1.25 kg?
702 cm3
A natural sample of uranium ore contains 5.35 g of uranium. How many uranium atoms are in the sample?
= 1.35 E22 atoms
5.35g * mol/238g * 6.022E23 atoms/mol
What are the quantum numbers (n and l) for the electrons in the d shell for iron?
n = 3, l = 2
n = shell #
l is orbital shape: 0 = s, 1 = p, 2 = d
Which would have the largest 2nd ionization energy? Na, Mg, Al, or Si?
Na. B/c removing 1st e- gives Na+ a stable noble gas electron config. removing 2nd e- would disrupt that.
How many H atoms are in 5.37 g of propane, C3H8?
5.37g * mol/44g * 8molH/mol * 6.022E23/mol = 5.88E23 atoms.