inorganic paper 1 Flashcards
What is an isotope?
Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons, resulting in different masses.
What is ionization energy?
Ionization energy is the energy required to remove one mole of electrons from one mole of atoms in the gaseous state.
What trend is observed in the reactivity of alkali metals as you go down the group
The reactivity increases as you move down Group 1 because the outer electron is further from the nucleus and more easily lost.
What happens to the reactivity of halogens as you move down Group 7?
Reactivity decreases as you go down the group because the atomic radius increases, making it harder to gain an electron.
What happens when Group 2 elements react with water?
They react with water to form hydroxides and hydrogen gas.
The reactivity increases down the group.
What is the definition of oxidation and reduction?
- Oxidation: The loss of electrons or an increase in oxidation state.
- Reduction: The gain of electrons or a decrease in oxidation state.
What is a characteristic property of transition metals?
Transition metals can form multiple oxidation states, often form colored compounds and conduct electricity
What is the test for halide ions (Cl⁻, Br⁻, I⁻)?
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)
How does the solubility of hydroxides change down Group 2?
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.
What is the test for carbonate ions (CO₃²⁻)?
Add dilute acid (e.g., HCl).
The formation of bubbles (carbon dioxide) indicates the presence of carbonate ions.
How do you test for sulfate ions (SO₄²⁻)? A
Add dilute hydrochloric acid (HCl) followed by barium chloride (BaCl₂).
A white precipitate forms
What is enthalpy of hydration ?
Hydration energy is the energy released when one mole of gaseous ions dissolves in water and forms an aqueous solution.
How does the atomic radius change as you move across a period (left to right)?
The atomic radius decreases across a period because the number of protons increases, pulling the electrons closer to the nucleus.
How does the atomic radius change as you move down a group?
The atomic radius increases down a group because additional electron shells are added, increasing the distance between the nucleus and the outer electrons.
How does ionization energy change as you move across a period?
Ionization energy increases across a period because the nuclear charge increases, making it harder to remove an electron as the atomic radius decreases.
How does ionization energy change as you move down a group?
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.
How does electronegativity change as you move across a period?
Electronegativity increases across a period because the nuclear charge increases, attracting electrons more strongly in a chemical bond.
How does electronegativity change as you move down a group?
Electronegativity decreases down a group because the atomic radius increases, making it harder for the nucleus to attract bonding electrons.
How do the melting and boiling points change as you move across Period 3 (Na to Ar)?
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).
How does the reactivity of alkali metals change down the group?
Reactivity increases down Group 1 because the outer electron is further from the nucleus and more easily lost due to increased shielding.
How does the reactivity of halogens change down the group?
Reactivity decreases down Group 7 because the atomic radius increases, making it harder for halogens to gain an electron.
What trend is observed in the first ionization energies of alkali metals as you move down the group?
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.
What trend is observed in the first ionization energies of halogens as you move down the group?
The first ionization energy decreases down Group 7 because the outer electrons are further from the nucleus and more shielded by inner electron shells.
How does the size of ions change across a period (left to right)?
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.
How does the size of atoms change as you move down a group?
The size increases down a group because additional electron shells are added, increasing the distance from the nucleus.
Why do noble gases not have electronegativity values?
Noble gases do not have electronegativity values because they have a full outer electron shell and do not readily form bonds with other elements.
How do oxidation states change across a period?
Oxidation states increase across a period as elements progress from metals (which tend to lose electrons) to nonmetals (which tend to gain electrons).
How does the reactivity of Group 2 elements change down the group?
Reactivity increases down Group 2 as the atoms get larger, and the outer electrons are more easily lost due to increased shielding.
why is there a deviation in ionization energy in period 3
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.
why is there a deviation in ionization energy in period 2
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.
why is there a deviation in atomic radius in period 3
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.
why is there a deviation in melting points in period 3
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.
What are the general properties of halogens (Group 7)?
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).
How does the reactivity of halogens change as you move down Group 7?
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.
What are the colors of the halogens at room temperature?
- 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).
How do the melting and boiling points of halogens change as you move down the group?
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).
What is the trend in the acidity of hydrogen halides in water?
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.
How does the oxidizing power of halogens change down Group 7?
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).
What happens when halogens react with alkali metals (e.g., sodium)?
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).
What are some common uses of halogen halides (e.g., NaCl, NaBr)?
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.
What are the general properties of Group 2 elements (alkaline earth metals)?
- 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⁺).
How do the melting points of Group 2 elements change as you move down the group?
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.
What happens when Group 2 metals react with water?
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.
Why is magnesium (Mg) an exception in its reaction with water compared to other Group 2 metals?
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.
How do Group 2 metals react with oxygen?
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.
How does the solubility of hydroxides change down Group 2?
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.
What are the colours for the falme test
- 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
what is the test results for dilute ammonia and halides
Add : dilute ammonia
* Chloride (Cl⁻): dissolves
* Bromide (Br⁻): insoluble
* Iodide (I⁻): insoluble
what is the test results for concentrated ammonia and halides
Add : dilute ammonia
* Chloride (Cl⁻): dissolves
* Bromide (Br⁻): dissolves
* Iodide (I⁻): insoluble
explain the physical properites of the halogens
All of the halogens exist as diatomic molecules. As the molecules get bigger there are more electrons which can move around and set up the temporary dipoles which create stronger intermolecular attractions as the molecules get bigger means their melting and boiling points rise.
what are the physcial properites of the halogens
- fluorine is a pale gas
- chlorine is a yellow gas
- bromine is a red brown liquid
- iodine a pruple solid
How are nitrogen oxides produced?
- N2 and O2 react at high temperatures
- in petrol engines
How can SO2 be identified?
- turns damp blue litmus paper red
- acidic gas
- forms H2SO4
How do boiling and melting points change as you move down group 7?
- increase
- larger atomic numbers
- more electrons
- larger instantaneous dipoles
- stronger Van der Waals forces
How does SiO2 react?
- acts as acid with a basic oxide
- forms silicate ion (SiO32-)
eg - SiO2 + CaO –> CaSiO3
What gas has a rotten egg smell?
H2S
What happens when magnesium is burned?
- bright white flame
- white powder forms
2Mg + O2 –> 2MgO
Mg + H2O –> MgO + H2
What happens when sodium bromide (NaBr) reacts with H2SO4? (equations and observations)
NaBr + H2SO4 –> NaHSO4 (s) + HBr (g)
- steamy white HBr fumes seen
H2SO4 + 2Br- + 2H+ –> SO2 + 2H2O + Br2 (l)
- exothermic (some Br2 vaporises)
- brown Br2 fumes
- colourless acidic SO2 formed
What happens when sodium chloride (NaCl) reacts with H2SO4?
NaCl (s) + H2SO4 (aq) –> NaHSO4 (s) + HCl (g)
- steamy white fumes of HCl
- can be used to prepare HCl
- acid-base reaction
- not redox
What happens when sodium fluoride (NaF) reacts with H2SO4?
NaF (s) + H2SO4 (aq) –> NaHSO4 (s) + HF (g)
- steamy white fumes of HF
- acid-base reaction
- not redox
What happens when sodium iodide (NaI) reacts with H2SO4? (equations and observations)
NaI + H2SO4 –> NaHSO4 (s) + HI (g)
- steamy white HI fumes
H2SO4 + 8I- + 8H+ –> H2S (g) + 4H2O + 4I2 (s)
- black solid iodine formed
- exothermic (some I2 vaporises)
- purple I2 fumes
- H2S has rotten egg smell
- colourless SO2 gas and yellow solid S formed as intermediates
What is the reaction for chlorine with alkali?
Cl2 + 2NaOH –> NaClO (aq) + NaCl (aq) + H2O
- cold, dilute NaOH
- disproportionation
What is the reaction of chlorine and water in sunlight?
2Cl2 (g) + 2H2O –> 4HCl + O2
pale green –> colourless
- causes chlorine to be lost from pool water
Why might uncatalysed reactions have high activation energies?
- negative ions may repel one another
- catalysed reaction may involve reactions between negative and positive ions
