Unit 3 - Atomic Structure and Properties

Question 1

UV wavelengths

Answer 1

10 nm

Question 2

Visible wavelengths

Answer 2

390 nm (purple) to 760 nm (red)

Question 3

Infrared wavelengths

Answer 3

10 000 nm

Question 4

Electromagnetic spectrum

Answer 4

radio waves - microwaves - infrared - visible - ultraviolet - X-rays - gamma rays

Question 5

Continuous spectra

Answer 5

results when the gas pressures are higher;

emission spectrum in which the lines overlap with each other and cannot be distinguised

Question 6

Line spectra

Answer 6

spectra that appears as specific discrete lines;
may be emission or absorption;
produced by passing electrical or thermal energy through gases

Question 7

Photoelectric effect

Answer 7

using small frequency (low energy), no electrons are ejected even after increasing intensity;
using large frequency (high energy), electrons were ejected but no additional ones after increasing intensity

Question 8

Louis deBroglie

Answer 8

proposed that all particles (including electrons) would also display wave properties;
massive particles have a short wavelength;
small particles have a longer wavelength

Question 9

Orbital

Answer 9

regions where there is a high probability of finding an electron;
has a high charge density

Question 10

Principal quantum number

Answer 10

describes how far the orbital extends from the nucleus;
denotes a shell;
values = 1 to infinity

Question 11

Orbital angular momentum quantum number

Answer 11

second quantum number;
denotes a subshell within a shell and describes the shape of the orbital;
values = 0 to n-1

Question 12

Magnetic quantum number

Answer 12

third quantum number;
describes the direction the orbital faces
values = - l to +l

Question 13

Electron spin quantum number

Answer 13

fourth quantum number;
does not apply to orbitals, but to electrons within the orbitals;
denotes the spin of the electron;
values = -1/2 or +1/2

Question 14

Diamagnetic vs. paramagnetic

Answer 14

diamagnetic = paired;
paramagnetic = unpaired

Question 15

Appearance of s, p, and d orbitals

Answer 15

s orbital = sphere;
p orbital = dumbbells;
d orbital = propellors

Question 16

Electrons and orbitals

Answer 16

in atoms with only one electron, all subshells within a shell have the same energy (degenerate);
in multi-electron atoms, electrons repel each other resulting in a different effective nuclear charge;
s is more stable than p which is more stable than d

Question 17

Pauli’s exclusion number

Answer 17

every electron in an atom has its own unique set of four quantum numbers

Question 18

Hund’s rule

Answer 18

electrons occupy singly, then they pair;

because a small amount of energy is required to pair

Question 19

Aufbau process

Answer 19

filling lower energy levels prior to higher energy levels;

produces lowest energy configuration

Question 20

Quantifying heavy metals

Answer 20

atomic absorption spectroscopy can be used to identify/quantify amounts of heavy metals (cadmium, lead);
each element has a distinct spacing among its electron energy levels;
each photon absorbed then corresponds to one metal ion, allowing quantification of the metal;
by comparison to a calibration curve, the amount can be determined

Question 21

Solar radiation and sunscreen

Answer 21

ultraviolet light is absorbed by sunscreens due to the absorption by oxybenzone;
the incoming photons are then absorbed, promoting the increase in energy, and do not affect the skin

Question 22

Photoelectric effect and solar cells

Answer 22

metals have different work functions for ejecting electrons from their surface;
semiconductors such as silicon work via the photoelectric effect, where the promoted electron crosses the band gap and does work through an external circuit;
each photon absorbed corresponds to one electron transition