UNIT 2 - Atomic Structure

Question 1

State the Hund’s rule of maximum multiplicity.

Answer 1

When filling degenerated orbitals electron fill all the orbitals singly before occupying them in pairs.

Question 2

State the most known contribution to the discovery of atomic structure made by E Rutherford.

Answer 2

gold foil experiment - firing alpha particles at a piece of gold foil

discovery of nucleus

Question 3

What does degenerated mean?

Answer 3

With equal energy.

Question 4

List the 2 exceptions in the electron configuration.

Answer 4

Cr:[Ar] 4s1 3d5
Cu:[Ar] 4s1 3d10

Question 5

Define the terms cation and anion.

Answer 5

cation - atom that lost electrons

anion - atom that gained electrons
changes in chemical properties

Question 6

State the Aufbau principle.

Answer 6

Means “building up” in German.

The electrons fill the lowest energy orbital that is available first.

Question 7

What does the statement “the energy of the atom is quantized” mean?

Answer 7

The electron cannot change its energy in a continuous way only by discrete amounts.

Question 8

Define valence electrons.

Answer 8

Positioned on the outer energy level.
Are mainly responsible for compound formation.

Question 9

Define the mass spectrometer.

Answer 9

Instrument enabling the measurement of the mass of individual atoms but we give relative atomic mass.

Question 10

List the components of an electromagnetic spectrum.

Answer 10

“Rabits mate in very unusual expensive garden”
- radio waves
- microwaves
- infrared radiation
- visible light (ROYGBIV)
- ultrared radiation
- x-rays
- gamma rays

Question 11

Distinguish absorption spectrum emission spectrum.

Answer 11

absorption - shows the radiation absorbed as atoms move from a lower to a higher energy level

emission - produced when an atom moves from a higher energy level to a lower one

Question 12

Define the term isotopes.

Answer 12

Atoms of the same element with different mass numbers, same chemical properties, different physical properties.

Question 13

State the most known contribution to the discovery of atomic structure made by Niels Bohr.

Answer 13

Positively charged nucleus and electrons travelling on orbits basically what we have today.

Question 13

Define the term electromagnetic radiation.

Answer 13

Energy the electron gives out when it falls down lower levels.

One packet of energy (quantum/photon) is released for each electron transition, the energy is proportional to the frequency of the radiation.

Question 14

State the Heisenberg’s Uncertainty Principle.

Answer 14

It is impossible to know where exactly an electron is at any given moment in time.

Question 15

Define the term first ionization energy.

Answer 15

Energy required to remove an electron from a neutral atom in gaseous state.

Question 15

State the most known contribution to the discovery of atomic structure made by JJ Thomson.

Answer 15

Plum pudding model of an atom (negative charged particles swim in positively charged sea) discovered electrons.

Question 16

State the relation between frequency and wavelength.

Answer 16

The shorter the wavelength the higher the frequency.

Question 17

Distinguish mass number from atomic number.

Answer 17

Mass number (A) describes the number of nucleons in an atom

Atomic number (Z) describes number of protons

Question 18

Define the term excited state.

Answer 18

unstable state of an electron that moved into an orbit or higher energy level when the atom absorbed energy.
Usually swiftly followed by a fall back to GROUND STATE.

Question 19

Name the atomic transitions of hydrogen.

Answer 19

Lyman series (to ground state).
Balmer series (to n=2)
Paschen series (to n=3)

Question 19

What is a paradigm shift?

Answer 19

Major change in the worldview, concepts and practices of how something works/ is accomplished.

Question 20

Explain why as the size of the atomic radius increases the IE decreases.

Answer 20

There are more shells so the force required to remove the electron is significantly lower as the attraction of the nucleus is lower as well.

Question 21

State the Pauli exclusion principle.

Answer 21

Any orbital can hold max of 2 electrons and these electrons must have opposite spins,
in an atom we cannot have 2 electrons with equal values of all quantum numbers so they must have at least different spin.

Question 21

Define the term wavelength.

Answer 21

Distance over which the shape of the wave repeats.

Distance between two successive crests or throughs.

Question 22

State the most known contribution to the discovery of atomic structure made by John Dalton.

Answer 22

Matter is made of small particles.
Defined atoms and compounds and that they cannot be neither created nor destroyed.

Question 23

Define the term element.

Answer 23

Substance that cannot be broken down into simpler substances in a chemical reaction
“atom” is derived from Greek “not able to be cut”.

Question 24

How can physical properties be measured?

Answer 24

Without changing the chemical composition of a substance.

Question 25

List the sub-atomic particles.

Answer 25

Nucleus: protons + electrons = nucleons
electrons

Question 26

Define the term compound.

Answer 26

Substance made by chemically combining two or more elements.

Has different properties from its constituent elements.

Question 27

Associate the emission spectrum of hydrogen with its regions of the electromagnetic spectrum.

Answer 27

Lyman = UV
Balmer = Visible
Paschen = Infrared

Question 28

Define the term frequency.

Answer 28

Number of waves that pass a particular point in 1s.