Unit 1

Question 1

How are elements arranged in the periodic table?

Answer 1

Are the range In order ofincreasing atomic number

Question 2

What does the position of an element in the periodic table allows chemists to predict?

Answer 2

It allows chemist to make accurate predictions of physical properties and chemical behaviours of the element.

Question 2

What are groups in the periodic table and what do elements within the same group having in common?

Answer 2

Groups are vertical columns in the periodic table elements within the same group have similar chemical properties due to having the same number of electrons in their outer shell

Question 3

What are periods in the periodic table and how do the properties of elements change across a period?

Answer 3

Periods are rows of elements arranged with increasing atomic number. Across a period the number of outer electrons increases and the properties of elements shift from metallic to non-metallic characteristics.

Question 4

Which element elements among the first 20 are classified as metallic?

Answer 4

Lithium (Li), Beryllium (Be), Sodium (Na), Magnesium (Mg), Aluminium (Al), Potassium (K), And calcium (Ca).

Question 5

What type of bonding is president in diatomic molecules like H2, N2, and O2.

Answer 5

These molecules exhibit covalent molecular bonding.

Question 6

What distinguishes covalent network structures and which Elements in the first 20 exhibit this type of structure.

Answer 6

Covalent network structures consist of items bonded in the continuous network. The element of the first 20 that exhibit this type of structure are boron (B), Carbon (In diamond and graphite forms), And silicon (Si).

Question 7

Why are noble gases described as monoatomic?

Answer 7

Noble gases exist as single atoms because they have full outer electron shells, making them chemically stable and non-reactive.

Question 8

What does the covalent Radius measure?

Answer 8

The covalent Radius is a measure of the size of an atom.

Question 9

How does the Covalent radius Change across a period?

Answer 9

The covalent radius decreases across a period due to an increasing nuclear charge which pulls the outer electrons closer to the nucleus.

Question 10

How does the covalent radius change down a group and why?

Answer 10

The covalent radius increases down a group because additional electron shells are occupied, increasing the distance between the outer electrons and the nucleus.

Question 11

What is the definition of first ionisation energy?

Answer 11

It is the energy required to remove one mole of electrons from one mole of gaseous atoms.

Question 12

How do second and subsequent ionisation energies differ from the first ionisation energy?

Answer 12

They refer to the energy required to remove additional molecules of electrons after the first electron has been removed.

Question 13

How does atomic size affect ionisation energy?

Answer 13

Larger atomic size decreases ionisation energy because the outer electrons are far from the nucleus and less tightly bound?

Question 14

What is the screening effect? And how does it influence ionisation energy?

Answer 14

The screening effect occurs when inner shell electron shield the outer electrons from the full attraction of the nucleus reducing ionisation energy.

Question 15

Why does ionisation energy increase across a period and decrease down a group?

Answer 15

Ionisation energy increases across a period due to a smaller atomic size and higher nuclear charge.
It decreases down a group because of large atomic size and increased screening effect.

Question 16

What is electronegativity and why is it important in bonding?

Answer 16

Electronegativity is a measure of the attraction an atom has for the bonding electrons. It is important because it determines how electrons are shared or transferred in a bond.

Question 17

How does nuclear charge influence electronegativity?

Answer 17

A higher nuclear charge increases electronegativity by exerting a stronger pull on bonding electrons.

Question 17

How does the covalent radius affect an elements electronegativity?

Answer 17

A smaller covalent radius increases electronegativity because the bonding electrons are closer to the nucleus and more strongly attracted.

Question 18

What role does the screening effect play in determining electronegativity trends across periods and down groups?.

Answer 18

The screening effect reduces electronegativity because it decreases the effective nuclear attraction felt by bonding electrons. This effect is more significant down a group where there are more inner electron shells.

Question 19

What is a covalent bond and how is it formed?

Answer 19

A covalent bond is formed when atoms share pairs of electrons.

Question 20

What holds two atoms together in a covalent bond?

Answer 20

Two positive nuclei are held together by their common attraction for their shared pair of electrons.

Question 21

How do polar covalent bonds differ from pure covalent bonds?

Answer 21

In polar covalent bonds, the atoms have different attractions for the bonding electrons resulting in partial charges on the atoms.
In pure covalent bonds the electrons are shared equally.

Question 22

What do Delta positive and Delta negative notations represent in polar covalent bonds?

Answer 22

These notations indicate partial charges on atoms due to the unequal sharing of bonding electrons, Which creates a dipole.

Question 23

What are ionic bonds, and how are they formed?

Answer 23

Ionic bonds are electrostatic attractions between positive and negative ion, Formed when electrons are transferred from one atom to another.

Question 24

What type of structure do ionic compounds form?

Answer 24

Ionic compounds form lattice structures of oppositely charged ions.

Question 25

What is the bonding continuum, and where do polar covalent bonds fit within it?

Answer 25

The bonding continuum represents the range of bonding types, From pure covalent to ionic. Polar covalent bonds lied between these two extremes.

Question 26

How does the difference in electronegativity between two atoms relate to the bond type?

Answer 26

The larger the electronegativity difference the more polar the bond. If the difference is very large, the bond becomes ionic.

Question 27

What happens when the difference in electronegativity is large enough to result in the formation of ions?

Answer 27

The bonding electrons are completely transferred from the atom with lower electronegativity to the atom with higher electronegativity, forming ions.

Question 28

Why are compounds formed between metals and non-metals often ionic?

Answer 28

Metals have low electronegativity and non-metals have high electronegativity, leading to a significant difference that favours ionic bonding.

Question 29

How can the physical properties of a compound, Such as melting point or electrical conductivity, Help helped deduce its type of bonding and structure?

Answer 29

Ionic compounds typically have high melting points, Are solid at room temperature, And conduct electricity when molten or dissolved. Covalent compounds have lower melting points and do not conduct electricity in most cases.

Question 30

What are intermolecular forces, And why are they necessary for substances to condense or freeze?

Answer 30

Intermolecular forces are attractive forces between molecules or atoms. They are necessary for condensation or freezing, As they hold the particles together in liquid or solid states.

Question 31

What are Van der Waals forces, And what type of interactions do they include?

Answer 31

Van der Waals forces are intermolecular forces that include London dispersion forces and permanent dipole-I permanent dipole interactions.

Question 32

What are London dispersion forces and how do they arise?

Answer 32

London dispersion forces are weak attraction ions caused by temporary dipoles and induced dipoles due to the movement of electrons and atoms and molecules.

Question 33

How does the number of electrons in an atom molecule affect the strength of London dispersion forces?

Answer 33

The strength of London dispersion forces increases with the number of electrons in an atom molecule

Question 34

What makes a molecule polar?

Answer 34

A molecule is polar if it has a permanent dipole which occur when there are an Uneven distribution of electron density due to differences in electronegativity.

Question 35

What are permanent dipole - permanent dipole Interactions and how do they compare in strength to London dispersion forces?.

Answer 35

Permanent dipole - permanent dipole interactions are electrostatic attractions between polar molecules. They are stronger than London dispersion forces for molecules with a similar number of electrons.

Question 36

What is hydrogen bonding and which elements commonly participate in it?

Answer 36

Hydrogen bonding is a strong dipole - Dipole interaction that occurs when hydrogen is bonded to high electronegative elements such as fluorine, Oxygen, Or nitrogen.

Question 37

How does the strength of hydrogen bonds compare to other types of intermolecular and covalent bonds?

Answer 37

Hydrogen bonds are stronger than other dipole - dipole interactions but weaker than covalent bonds.

Question 38

How do the nature and strength of intermolecular forces influence melting points, boiling points, and viscosity?

Answer 38

Stronger intermolecular forces result in higher melting points, boiling points, and viscosity as more energy is needed to overcome the attraction.

Question 39

Why do polar substances generally have higher melting and boiling points than non-polar substances with a similar number of electrons?

Answer 39

Polar substances have stronger dipole-dipole interactions, which require more energy to break compared to the weaker London dispersion forces in non-polar substances.

Question 40

What is the cause of the anomalous boiling points of ammonia, water, and hydrogen fluoride?

Answer 40

Their anomalous boiling points are due to strong hydrogen bonding between molecules.

Question 41

How does the hydrogen bonding affect the density of ice compared to water at low temperatures?

Answer 41

Hydrogen bonding in ice creates an expanded structure, making ice less dense than water.

Question 41

Why are ionic compounds and polar molecular compounds soluble in polar solvents like water?

Answer 41

The partial charges in polar solvents can interact with and stabilise the ions or dipoles in the solute, allowing it to dissolve.

Question 42

Why are non-polar molecular substances soluble in non-polar solvents but insoluble in polar solvents?

Answer 42

Non-polar substances dissolve in non-polar solvents due to similar intermolecular forces, but they do not interact well with the dipoles in polar solvents.

Question 43

What molecular features, such as O-H or N-N bonds, indicate potential hydrogen bonding?

Answer 43

The presence of O-H or N-N bonds implies potential hydrogen binding due to the high electronegativity of oxygen and nitrogen.

Question 44

How can the spatial arrangement of polar covalent bonds result in a molecule having a permanent dipole?

Answer 44

If the polar covalent bonds are arranged asymmetrically, the molecule will have an overall permanent dipole.

Question 45

What properties of a compound are influences by hydrogen bonding, and how?

Answer 45

Hydrogen binding affects melting points, boiling points, viscosity and solubility, often increasing them due to the strong intermolecular forces.

Question 46

What factors should be considered to predict the solubility of a compound?

Answer 46

Consider the presence of O-H or N-H bonds (indicating hydrogen bonding) and the spatial arrangement of polar covalent bonds, which might result in a permanent dipole,

Question 47

What is reduction in terms of electron transfer?

Answer 47

Reduction is the gain of electrons by a reactant in any reaction.

Question 48

What is oxidation in terms of electron transfer?

Answer 48

Oxidation is the loss of electrons by a reactant in any reaction.

Question 49

What is a redox reaction?

Answer 49

A redox reaction is a reaction where reduction and oxidation take place at the same time?

Question 50

What is an oxidising agent and how does it behave in a redox reaction?

Answer 50

An oxidising agent as a substance That accepts electrons from another reactant.

Question 51

What is a reducing agent and how does it behave in a redox reaction?

Answer 51

A reducing agent is a substance that donates electrons to another reactant.

Question 52

How can oxidising and reducing agents be identified in redox reactions?

Answer 52

Oxidising agents are identified as the substances gaining electrons, while reducing agents are identified as those losing electrons.

Question 53

Why do elements which low electro negativities act as reducing agents?

Answer 53

Elements with low electro negativities tend to lose electrons easily, making them reducing agents.

Question 54

Why do elements with high electro negativities act as oxidising agents?

Answer 54

Elements with high electro negativities tend to gain electrons, making them oxidising agents.

Question 55

Where in the periodic table are the strongest reducing agents found?

Answer 55

The strongest reducing agents are found in group one of the periodic table.

Question 56

Where in the periodic table are the strongest oxidising agents found?

Answer 56

The strongest oxidising agents are found in group 7 of the periodic table.

Question 57

Name a molecule that acts as a strong oxidising agent?

Answer 57

Hydrogen peroxide is a molecule that acts as a strong oxidising agent.

Question 58

Which group ions are strong oxidising agents in acidic solutions?

Answer 58

Dichromate and potassium ions are strong oxidising agents in acidic solutions?

Question 59

What gas can act as a reducing agent?

Answer 59

Carbon monoxide is a gas that can act as a reducing agent.

Question 60

Why are oxidising agents effective in killing fungi and bacteria?

Answer 60

Oxidising agents are effective in killing fungi and bacteria because of their ability to oxidise biological molecules.

Question 61

How are oxidising agents used in inactivating viruses?

Answer 61

Oxidising agents inactivate viruses by breaking down their biological structures through oxidation.

Question 62

Why are oxidising agents suitable for use as bleaches for clothes and hair?

Answer 62

Oxidising agents break down coloured compounds effectively, making them ideal for use as bleaches for clothes and hair.

Question 63

What does the electrochemical series represent?

Answer 63

The electrochemical series represents a series of reduction reactions.

Question 63

Where are the strongest oxidising agents located in the electrochemical series?

Answer 63

The strongest oxidising agents are located at the bottom of the left-hand column of the electric chemical series.

Question 64

Where are the strongest reducing ages located in the electrochemical series?

Answer 64

The strongest reducing agents are located at the top of the right hand column of the electrochemical series.

Question 65

What components can be added to balance and ion-electron equation?

Answer 65

Water molecules, hydrogen ions, and electrons can be added to balance an ion-electron equations.

Question 66

How can ion electron equations be combined to produce redox equations?

Answer 66

Ion-electron equations can be combined by ensuring the number of electrons lost in oxidation equals the number of electrons gained in the reduction, resulting in a balanced overall redox equation.