Chemistry 1 Marks Question

It is because of low ionisation enthalpy. They can lose electrons easily, that is why they are strong reducing agents.

Lithium shows diagonal relationship with magnesium due to similar charge over radius ratio.

MF < MCI < MBr < MI, lesser the difference in electronegativity, more will be covalent character.

They are soft metals due to less force of attraction between positively charged kernels and valence electrons cloud and due to large atomic size, i.e., weak metallic bond.

Dicalcium silicate (26%), tricalcium silicate (51%) and tricalcium aluminate (11%).

CsH < RbH < KH < NaH < LiH.
Smaller the atom, stronger will be the bond with hydrogen, more stable.

Be resembles Al because charge over radius ratio is similar, i.e., they have similar polarizing power.

Brine is an aqueous solution of sodium chloride.

It is because it is covalent, gets hydrolysed forming HCI which fumes in moist air.

They have low ionisation enthalpy and can lose electrons when light falls on them, that is why they are used in photoelectric cells.

It is due to weak metallic bonds which is due to bigger atomic size that is why they have low melting and boiling points.

1. It is a mild antiseptic for skin infections.
2. It is used in fire extinguishers.

Fly ash is waste product of iron industry and thermal power plants. Its properties are similar to cement because it mainly consist of calcium silicate, therefore, can be used as cement substitute.

Beryllium.

It is because metal nitrates are highly unstable and highly soluble in water due to higher hydration energy than lattice energy. Therefore, rarely found as ores.

This is because sodium produces hydrogen gas with water which catches fire because of the exothermic nature of the reaction.

It contains sodium sulphate, calcium sulphate, calcium chloride and magnesium chloride as impurities.

Na < K < Rb < Cs < Li.

It acts as reducing agent.

NaI < NaBr < NaCl < NaF. Greater the difference in electronegativity more will be ionic character, higher will be melting point.

Alkali metals have bigger atomic size, therefore, they have lower first I.E. than group 2 elements.

1. Potassium helps in proper functioning of heart, kidney, and other vital organs. It reduces blood pressure.
2. Calcium is essential for bones and teeth, therefore, we must take source of calcium every day.

LiCl has lowest melting point because it is covalent.

Sodium hydroxide (NaOH).

They have strong metallic bonds due to smaller size and have more number of valence electrons.

LiCl < NaCl < KCI < CsCl because greater the electropositive character of metal, more will ionic character of the compound.

Both sodium hydroxide and potassium hydroxide are highly deliquescent. It absorbs moisture from air and changes into solution (after sometime).

K has lower ionisation enthalpy than Na due to bigger atomic size, therefore, it is more reactive.

It is because their hydroxides are soluble bases called alkalies. Secondly their ashes are alkaline in nature.

Limestone, chalk, marble.

Due to weak metallic bonds and large atomic size, their density is low.

It is due to largest atomic size, they can lose electrons easily.

Gypsum is added, only to slow down this process, so that it gets sufficiently hardened.

Alkali metals acquire, noble gas configuration after losing I electron, therefore their second ionisation energy is higher than alkaline earth metals.