inorganic I (p1)

Question 1

What is an isotope?

Answer 1

Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons, resulting in different masses.

Question 2

What is ionization energy?

Answer 2

Ionization energy is the energy required to remove one mole of electrons from one mole of atoms in the gaseous state.

Question 3

What trend is observed in the reactivity of alkali metals as you go down the group

Answer 3

The reactivity increases as you move down Group 1 because the outer electron is further from the nucleus and more easily lost.

Question 4

What happens to the reactivity of halogens as you move down Group 7?

Answer 4

Reactivity decreases as you go down the group because the atomic radius increases, making it harder to gain an electron.

Question 5

What happens when Group 2 elements react with water?

Answer 5

They react with water to form hydroxides and hydrogen gas. The reactivity increases down the group.

Question 6

What is the definition of oxidation and reduction?

Answer 6

• Oxidation: The loss of electrons or an increase in oxidation state.
• Reduction: The gain of electrons or a decrease in oxidation state.

Question 7

What is a characteristic property of transition metals?

Answer 7

Transition metals can form multiple oxidation states and often form colored compounds.

Question 8

What is the test for halide ions (Cl⁻, Br⁻, I⁻)? A

Answer 8

Add dilute nitric acid (HNO₃) followed by silver nitrate (AgNO₃):
* Chloride (Cl⁻): White precipitate (AgCl)
* Bromide (Br⁻): Cream precipitate (AgBr)
* Iodide (I⁻): Yellow precipitate (AgI)

Question 9

How does the solubility of hydroxides change down Group 2?

Answer 9

The solubility of Group 2 hydroxides increases as you go down the group, e.g., magnesium hydroxide (Mg(OH)₂) is only slightly soluble, but barium hydroxide (Ba(OH)₂) is much more soluble.

Question 10

What is the test for carbonate ions (CO₃²⁻)?

Answer 10

Add dilute acid (e.g., HCl). The formation of bubbles (carbon dioxide) indicates the presence of carbonate ions.

Question 11

How do you test for sulfate ions (SO₄²⁻)? A

Answer 11

Add dilute hydrochloric acid (HCl) followed by barium chloride (BaCl₂). A white precipitate of barium sulfate (BaSO₄) confirms the presence of sulfate ions.

Question 12

What is enthalpy of hydration ?

Answer 12

Hydration energy is the energy released when one mole of gaseous ions dissolves in water and forms an aqueous solution.

Question 13

How does the atomic radius change as you move across a period (left to right)?

Answer 13

The atomic radius decreases across a period because the number of protons increases, pulling the electrons closer to the nucleus.

Question 14

How does the atomic radius change as you move down a group?

Answer 14

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

Question 15

How does ionization energy change as you move across a period?

Answer 15

Ionization energy increases across a period because the nuclear charge increases, making it harder to remove an electron as the atomic radius decreases.

Question 16

How does ionization energy change as you move down a group?

Answer 16

Ionization energy decreases down a group because the outer electrons are further from the nucleus and experience more shielding from inner electron shells, making it easier to remove an electron.

Question 17

How does electronegativity change as you move across a period?

Answer 17

Electronegativity increases across a period because the nuclear charge increases, attracting electrons more strongly in a chemical bond.

Question 18

How does electronegativity change as you move down a group?

Answer 18

Electronegativity decreases down a group because the atomic radius increases, making it harder for the nucleus to attract bonding electrons.

Question 19

How do the melting and boiling points change as you move across Period 3 (Na to Ar)?

Answer 19

Melting and boiling points increase from Na to Si (strong metallic and covalent bonding), then decrease from Si to Ar (weak London forces in molecular structures like P₄, S₈, Cl₂, and Ar).

Question 20

How does the reactivity of alkali metals change down the group?

Answer 20

Reactivity increases down Group 1 because the outer electron is further from the nucleus and more easily lost due to increased shielding.

Question 21

How does the reactivity of halogens change down the group?

Answer 21

Reactivity decreases down Group 7 because the atomic radius increases, making it harder for halogens to gain an electron.

Question 22

What trend is observed in the first ionization energies of alkali metals as you move down the group?

Answer 22

The first ionization energy decreases down Group 1 because the outer electron is further from the nucleus and more shielded, making it easier to remove.

Question 23

What trend is observed in the first ionization energies of halogens as you move down the group?

Answer 23

The first ionization energy decreases down Group 7 because the outer electrons are further from the nucleus and more shielded by inner electron shells.

Question 24

How does the size of ions change across a period (left to right)?

Answer 24

Across a period, the size of cations decreases and the size of anions decreases as the nuclear charge increases, pulling the electrons closer to the nucleus.

Question 25

How does the size of ions change as you move down a group?

Answer 25

The size of both cations and anions increases down a group because additional electron shells are added, increasing the distance from the nucleus.

Question 26

Why do noble gases not have electronegativity values?

Answer 26

Noble gases do not have electronegativity values because they have a full outer electron shell and do not readily form bonds with other elements.

Question 27

How does metallic character change across a period?

Answer 27

Metallic character decreases across a period as atoms gain more valence electrons and tend to form covalent bonds rather than metallic bonds.

Question 28

How does metallic character change down a group

Answer 28

Metallic character increases down a group because atoms become larger, and their outer electrons are more easily lost, which makes them more likely to exhibit metallic behavior.

Question 29

What types of structures and bonding are present across Period 3?

Answer 29

• Na to Si: Metallic or covalent structures (metallic bonding in Na, Mg, Al; giant covalent structure in Si).
• P, S, Cl: Simple molecular structures with covalent bonding.
• Ar: Monatomic with weak London dispersion forces between atoms.

Question 30

How do oxidation states change across a period?

Answer 30

Oxidation states increase across a period as elements progress from metals (which tend to lose electrons) to nonmetals (which tend to gain electrons).

Question 31

How does the reactivity of Group 2 elements change down the group?

Answer 31

Reactivity increases down Group 2 as the atoms get larger, and the outer electrons are more easily lost due to increased shielding.

Question 32

why is there a deviation in ionization energy in period 3

Answer 32

The first ionization energy of aluminium is lower because the outer electron in aluminium is in a 3p orbital, which is higher in energy and further from the nucleus than the 3s orbital in magnesium. This makes it easier to remove.

Question 33

why is there a deviation in ionization energy in period 2

Answer 33

The first ionization energy of oxygen is lower because in oxygen, the 2p orbital is paired, creating repulsion between the two electrons. In nitrogen, the 3 unpaired electrons in the 2p orbitals provide extra stability, making it harder to remove an electron.

Question 34

why is there a deviation in atomic radius in period 3

Answer 34

Despite being in the same period, aluminium has a smaller atomic radius because it has a higher nuclear charge (13 protons vs. 12 protons in magnesium), which pulls the electrons closer to the nucleus, reducing the size.

Question 35

why is there a deviation in melting points in period 3

Answer 35

Sulfur has a larger molecular structure (S₈ molecules), which results in stronger London forces between the molecules compared to phosphorus (P₄ molecules), leading to a higher melting point.

Question 36

What are the general properties of halogens (Group 7)?

Answer 36

Halogens are nonmetals with:
* Low melting and boiling points (increase down the group),
* High electronegativity (decreases down the group),
* Form halide ions (X⁻) when they gain an electron,
* Reactive with metals to form salts (e.g., sodium chloride, NaCl).

Question 37

How does the reactivity of halogens change as you move down Group 7?

Answer 37

The reactivity decreases down the group because as the atomic size increases, the outer electron is farther from the nucleus and more shielded, making it harder for the halogens to gain an electron.

Question 38

What are the colors of the halogens at room temperature?

Answer 38

• Fluorine (F₂): Pale yellow gas,
• Chlorine (Cl₂): Yellow-green gas,
• Bromine (Br₂): Red-brown liquid,
• Iodine (I₂): Shiny black solid, purple vapor,
• Astatine (At₂): Rare, thought to be metallic or dark brown solid (due to its radioactivity).

Question 39

How do the melting and boiling points of halogens change as you move down the group?

Answer 39

The melting and boiling points increase down Group 7 as the size of the molecules increases, leading to stronger London dispersion forces between molecules (e.g., fluorine has a low melting point, while iodine has a much higher melting point).

Question 40

What is the trend in the acidity of hydrogen halides in water?

Answer 40

The acidity of hydrogen halides increases down the group because as the halogen size increases, the H–X bond becomes weaker, making it easier to dissociate in water. HF is the weakest acid, while HI is the strongest.

Question 41

How does the oxidizing power of halogens change down Group 7?

Answer 41

The oxidizing power decreases down the group because larger halogen atoms have more electron shielding and are less able to attract and accept electrons (e.g., fluorine is a strong oxidizer, iodine is weak).

Question 42

What happens when halogens react with alkali metals (e.g., sodium)?

Answer 42

When alkali metals react with halogens, they form ionic salts (e.g., sodium chloride, NaCl) by transferring an electron from the metal to the halogen. The metal is oxidized (loses an electron), and the halogen is reduced (gains an electron).

Question 43

What are some common uses of halogen halides (e.g., NaCl, NaBr)?

Answer 43

Halogen halides are used in a variety of applications:
* Sodium chloride (NaCl): Table salt, used in industry, food preservation.
* Sodium bromide (NaBr): Used in photography and in the production of bromine.
* Potassium iodide (KI): Used in medical applications as a source of iodine.

Question 44

What are the general properties of Group 2 elements (alkaline earth metals)?

Answer 44

• Shiny and silvery-white metals,
• Good conductors of heat and electricity,
• Less reactive than Group 1 metals but still reactive,
• Form basic oxides and hydroxides (e.g., CaO, Mg(OH)₂),
• Typically have two valence electrons and form 2⁺ ions (e.g., Mg²⁺, Ca²⁺).

Question 45

How do the melting points of Group 2 elements change as you move down the group?

Answer 45

The melting points generally decrease down the group due to weaker metallic bonding as the atoms get larger, and the delocalized electrons are further from the nucleus and less tightly held.

Question 46

What happens when Group 2 metals react with water?

Answer 46

Group 2 metals react with water to form metal hydroxides and hydrogen gas. The reaction becomes more vigorous down the group:
* Magnesium (Mg) reacts slowly with cold water but more rapidly with steam.
* Calcium (Ca), strontium (Sr), and barium (Ba) react more vigorously with cold water.

Question 47

Why is magnesium (Mg) an exception in its reaction with water compared to other Group 2 metals?

Answer 47

Magnesium reacts slowly with cold water because a layer of magnesium hydroxide (Mg(OH)₂) forms on its surface, which acts as a protective barrier, slowing further reaction. However, magnesium reacts more readily with steam.

Question 48

How do Group 2 metals react with oxygen?

Answer 48

Group 2 metals react with oxygen to form metal oxides. The reaction becomes more vigorous as you go down the group:
* Magnesium (Mg) forms a white solid MgO.
* Calcium (Ca) forms a white solid CaO.
* Barium (Ba) forms BaO and may produce a yellow flame in the process.

Question 49

How does the solubility of hydroxides change down Group 2?

Answer 49

The solubility of Group 2 hydroxides in water increases down the group:
* Magnesium hydroxide (Mg(OH)₂) is insoluble in water, used as an antacid.
* Calcium hydroxide (Ca(OH)₂) is sparingly soluble and forms limewater.
* Barium hydroxide (Ba(OH)₂) is highly soluble.

Question 50

What are the colours for the falme test

Answer 50

• lithium (Li): brick red
• Calcium (Ca): Orange-red flame.
• Sodium (Na): yellow flame.
• copper (Co): Green flame.
• potassium (K): lilac flame
• chnage these to flame test ones

Question 51

what is the test results for dilute ammonia and halides

Answer 51

Add : dilute ammonia
* Chloride (Cl⁻): dissolves
* Bromide (Br⁻): insoluble
* Iodide (I⁻): insoluble

Question 52

what is the test results for concentrated ammonia and halides

Answer 52

Add : dilute ammonia
* Chloride (Cl⁻): dissolves
* Bromide (Br⁻): dissolves
* Iodide (I⁻): insoluble