Unit 1 AoS1- The Periodic Table

Question 0

Define excited state.

Answer 0

The excited state is the state of an atom, ion, etc. in which one or more electrons have absorbed energy and are not in their lowest energy levels.

Question 1

What does the Law of Conservation of Mass state?

Answer 1

The law of conservation of mass states that during a chemical reaction, the mass of the reactants must equal to the mass of the products.

Question 2

Define ground state.

Answer 2

The ground state is a term used to describe atoms in which the elections are in their lowest possible energy levels.

Question 3

What are the sub- atomic particles?

Answer 3

Protons, neutrons and electrons.

Question 4

What are isotopes?

Answer 4

Isotopes are atoms with the same atomic number but different mass numbers, therefore they have a varying number of neutrons.

Question 5

Who discovered the neutron?

Answer 5

James Chadwick

Question 6

Who is responsible for the discovery of the nucleus and the protons within it, and through what experiment was this discovery based on?

Answer 6

Ernest Rutherford discovered this through the Gold Foil experiment.

Question 7

Who discovered the electron and through what experiment was the discovery based on?

Answer 7

J.J Thompson discovered the electron through the cathode ray experiment.

Question 8

Who was the scientist who proposed an early atomic model and what was the name of this model?

Answer 8

J. J Thompson designed the plum pudding model where he concluded that atoms consist of a sphere of positive matter in which electrons were embedded randomly like plums in a pudding.

Question 9

What is ionization energy?

Answer 9

It is energy required for the removal of an electron from the outer shell of a gaseous atom.

Question 10

What does it mean if an atom has lower ionization energy?

Answer 10

Lower ionization energy makes it easier to remove the valence electron.

Question 11

What are the four subshells, in order?

Answer 11

S, P, D, F

Question 12

What are lanthanides?

Answer 12

The set of elements with atomic numbers from 58 and 71, in which the 4f-subshells are progressively being filled.

Question 13

What are actinides?

Answer 13

The set of elements with atomic number between 90 and 103, in which the 5f-subshells are progressively filled.

Question 14

First ionization is governed by what 4 factors?

Answer 14

1) the charge on the nucleus
2) the distance of the outer electron from the nucleus
3) the amount of screening by inner electrons
4) location of the electron being removed in terms of its orbital and how many electrons are present in that orbital

Question 15

Going down the periodic table groups, what happens to the ionization energy?

Answer 15

There is a drop in ionization energy.

Question 16

Going across the periodic table periods, what happens to the ionization energy?

Answer 16

The ionization energy increases, making it harder to remove the outer electron.

Question 17

What is the second ionization energy?

Answer 17

It is the energy needed to remove a second electron from each ion in 1 mole of gaseous +1 ions to give gaseous +2 ions.

Question 18

How do you find the group of an element using the successive ionization energies?

Answer 18

The big gap between two successive ionization energies is typical of removing an election from the inner energy level, therefore from the successive ionization, it can be figured out what group the element is from.

Question 19

What are the two exceptional electronic configurations?

Answer 19

Cr (24) has an electronic configuration of 4s1, 3d5 in order to gain a half-filled stable d-subshell configuration and Cu (29) has an electronic configuration of 4s1, 3d10 in order to gain a full-filled stable d-subshell configuration.

Question 20

What is the modern periodic table based on and why does it not follow Mendeleev’s periodic law?

Answer 20

The modern periodic table is based on atomic number because atomic weight is not a good parameter to distinguish between two elements due to isotopes.

Question 21

What is Mendeleev’s periodic law?

Answer 21

Mendeleev proposed that the properties of elements vary periodically with their atomic weights.

Question 22

What is a combination reaction?

Answer 22

2 or more reactants join to form a compound.

Question 23

What is a decomposition reaction?

Answer 23

The breakdown of a reactant into 2 or more products.

Question 24

What is a displacement reaction?

Answer 24

When a more reactive metal reacts with a solution of a less reactive metal, the more reactive metal will displace the less reactive metal from its solution.

Question 25

What is a precipitation reaction?

Answer 25

Aka double displacement. When 2 compounds react to form 2 new compounds, of which one is insoluble (precipitate (s)).

Question 26

What is a neutralisation reaction?

Answer 26

When an acid (usually starts with H) and a base (usually ends in OH) react to give a salt and water.

Question 27

What is a combustion reaction?

Answer 27

When a hydrocarbon (CxHy) reacts with oxygen (O2), the products are carbon dioxide (CO2) and water (H2O).

Question 28

What is an endothermic reaction?

Answer 28

Energy is supplied from surroundings for the reaction to happen and the reactants have less energy than the products.

Question 29

What is an exothermic reaction?

Answer 29

The energy is released into the surroundings when the reaction happens and the reactants have more energy than the products.

Question 30

What happens to the atomic size down the group?

Answer 30

Atomic size increases due to an increase in the number of shells.

Question 31

What is electronegativity?

Answer 31

It is the measure of the ability of an atom to attract an electron towards itself.

Question 32

What happens to first ionization energy and electronegativity down the group?

Answer 32

They decrease because there is weak nuclear attraction.

Question 33

What happens to the chemical reactivity of metals and metallic character of atoms down the periodic table group?

Answer 33

They increase due to weak nuclear attraction, therefore it being easier to lose electrons.

Question 34

What happens to the chemical reactivity of non-metals and the non- metallic character of elements down a group?

Answer 34

They decrease due to a weak nuclear attraction, making it harder to gain electrons.

Question 35

What happens to atomic size across the period?

Answer 35

Atomic size decreases due to an increasing core charge.

Question 36

What happens to first ionization energy and electronegativity across a period?

Answer 36

They increase due to a strong nuclear attraction.

Question 37

What happens to chemical reactivity of metals and metallic character across the period?

Answer 37

They decrease due to a strong nuclear attraction, making it harder to lose valence electrons.

Question 38

What happens to the chemical reactivity in non-metals and the non-metallic character of elements across a period?

Answer 38

They increase due to a strong nuclear attraction, making it easier to gain electrons.

Question 39

Define metallic character?

Answer 39

How easily an atom in an element can lose electrons.

Question 40

Define non-metallic character?

Answer 40

How easily an atom in an element can gain electrons.

Question 41

What is Dalton’s theory?

Answer 41

1) all matter consists of indivisible atoms. FALSE.
2) atoms of a particular element are identical in weight and have identical properties. FALSE.
3) atoms are neither created nor destroyed in reactions. TRUE.
4) compounds are formed from the combination of 2 or more elements. TRUE.
5) the proportion and type/kind of atoms is fixed in a given compound. TRUE.
6) atoms combine in simple, numerical ratios. TRUE.

Question 42

What did Rutherford’s model propose?

Answer 42

That the electrons move in circular orbits around the nucleus with an electrostatic force of attraction between the positively charged nucleus and the negatively charged electrons.

Question 43

Who refined Rutherford’s model and what did they propose?

Answer 43

Neils Bohr proposed that electrons in atoms:

• circled the nucleus without losing energy
• could only move in certain fixed orbits of particular energies.
• the closer the shell to the nucleus, the greater the attraction
• the further the shell from the nucleus, the greater the energy level.
• when valence electron jumps to the higher electron, it goes through electron excitation. The excited state is unstable.
• when the electron returns to the ground state, because of instability, it releases the gained energy as light.

Question 44

What is the general rule when writing electronic configuration in the preliminary configuration method?

Answer 44

You cannot add more than 8 electrons in the 3rd shell, unless the 4th shell is filled with atleast 2 electrons.

Question 45

What does the S block of elements contain?

Answer 45

Group 1 (alkali metals) and group 2 (alkaline earth metals). These elements have a half filled (s1) or full filled (s2) a subshell as the highest energy level.

Question 46

What does the P block of elements contain?

Answer 46

Contains elements in groups 13-18. P subshell is the highest energy subshell. Elements have outer shell configurations from s2p1 to s2p6.

Question 47

What does the D block elements contain?

Answer 47

Contains elements known as transition metals located in between S and P blocks, having outer shell configuration from d1s2 to d10s2.

Question 48

What does the F block of elements contain?

Answer 48

Contains lanthanides where 4f subshell is progressively being filled and actinides where 5f subshell is progressively being filled.