Chapter 2: Elements and the periodic table

Question 1

What is an isotope?

Answer 1

An element that contain equal numbers of protons but different numbers of neutrons

Question 2

What are the three subatomic particles

Answer 2

Protons, neutrons and electrons

Question 3

What is an atom

Answer 3

The building blocks of matter

Question 4

What is a molecule?

Answer 4

A group of two or more atoms covalently bonded

Question 5

What is an ion?

Answer 5

A charged atom

Question 6

Shell configuration vs subshell configuration

Answer 6

The shell configuration is the amount of electrons per shell (e.g 2,8,8,1). Subshell configuration is an electron configuration that uses the subshells and blocks on the periodic table (e.g 1s^2 2s^2 2p^6)

Question 7

List the differences from the Bohr and Schrödinger model

Answer 7

Bohr:
- cannot accurately predict the emission spectra of atoms with more than one
electron
- is unable to explain why electron shells can only hold 2n^2 electrons
- does not explain ,why the fourth shell accepts two electrons before the third shell
is completely filled.

Schrödinger:
- there are major energy levels in atom called shells
- these shells contain seperate energy levels called subshells
- each subshell is made up of orbitals. They can be described as regions of space surrounding the nucleus of an atom in which electrons may be found. Any orbital can hold a maximum of two electrons.

Question 8

What are critical elements?

Answer 8

Critical elements are elements that are heavily relied on in industry and society in areas such as renewable energy, electronics, food supply and medicine. Some critical elements include copper, gold and tin.

Question 9

List six trends in the periodic table

Answer 9

1. Electronegativity
2. Atomic Radii
3. First Ionisation Energy
4. Core Charge
5. Metallica Character
6. Non-Metallic Character

Question 10

What is electronegativity?

Answer 10

Electronegativity is the ability to attract electrons to itself.

Question 11

Describe the trends for electronegativity on the periodic table

Answer 11

When going left to right on the periodic table, electronegativity increases because the valence electrons are less strongly attracted to the nucleus as they are further away from the nucleus.

When going down a group on the periodic table, electronegativity decreases because the valence electrons become more strongly attracted to the nucleus as the core charge increases the valence electrons become more strongly attracted to the nucleus

Question 12

What is atomic radii?

Answer 12

Atomic radius is a measurement used for the size of atoms. It can be regarded as the distance from the nucleus to the valence shell electrons

Question 13

Describe the trends for atomic radii on the periodic table

Answer 13

When going left to right on the periodic table, atomic radii decreases because the core charge increases.

When going down a group on the periodic table, the atomic radii increase because there are more shells

Question 14

What is core charge?

Answer 14

The core charge (effective nuclear charge) of an atom is a measure of the attractive force felt by the valence shell electrons towards the nucleus.

Question 15

What is the formula for core charge?

Answer 15

Core charge = number of protons in the nucleus - number of total inner shell electrons

Question 16

Describe the trends of core charge on the periodic table

Answer 16

When going left to right on the periodic table, core charge increases because the valence electrons are more attracted to the nucleus

When going down a group on the periodic table, core charge remains constant because valence electrons are held less strongly because they are further away from the nucleus.

Question 17

What is first ionisation energy?

Answer 17

The energy required to remove one electron from an atom of an element in the gas phase

Question 18

Describe the trends of first ionisation energy on the periodic tale

Answer 18

When going left to right on the periodic table, first ionisation energy increases because the core charge increases.

When going down a group on the periodic table, first ionisation energy decreases the valence electrons are less attracted to the nucleus because they are away from the nucleus

Question 19

What is metallic character?

Answer 19

Metallic character refers to the level of reactivity of a metal

Question 20

Describe the trend of metallic character on the periodic table

Answer 20

When going left to right on on the periodic table, the metallic character decreases because of the tendency of atoms to lose or gain electrons when going across a period

When going down a group on the periodic table, the metallic character increases The metallic character of an element depends on how readily it can lose its electrons and since the size of an atom increases causing a lesser attraction between the nuclei and the electrons

Question 21

What is nonmetallic character?

Answer 21

Non-metallic character relates to the tendency to accept electrons during chemical reactions.

Question 22

Describe the trends of the non-metallic character on the periodic table

Answer 22

When going left to right on the periodic table, the nonmetallic character increases because it is easier to gain electrons when moving left to right

When going down a group on the periodic table, the nonmetallic character decreases because it becomes more difficult to gain electrons

Question 23

Describe the reactivity of metals and non-metals in relation to the periodic table

Answer 23

For metals, the more down you go down a group, the weaker electrostatic force between nucleus and electrons, but the more reactive

For non-metals, the more down you go down a group, the the weaker electrostatic force between nucleus and electrons but less reactive