s & p elements

Question 1

Potassium can displace Na from NaCl due to

Answer 1

Potassium is more electropositive than Na, so it displace Na from compounds

Question 2

Sodium burns in chlorine with __________ flame.

Answer 2

orange

Question 3

1s orbital contributes to maximum screening in:

Answer 3

Iodine has smallest is orbital in all due to greatest nuclear charge on it. So its contribution in screening is maximum.

Question 4

Which elements can form more than 5 bonds normally?

Answer 4

Iodine can form upto 7 bonds due to hyper valance as in IF7.

Question 5

Which one of the following properties of IIA group elements increases down the group?

Answer 5

reducing power of IIA group elements increase down the group and electropositivity and reactivity. As a result ionization energy decreases and metallic character increases.

Question 6

Which orbital contributes least to screening of electron?

Answer 6

f – orbital is least penetrating so its screening is least.

Question 7

Excess methane reacts with chlorine. The major product is

Answer 7

Chloromethane
In excess alkane, monosubstituted product is favored.
In limited alkane, tetrasubstituted product is favored.

Question 8

In heterocyclic compounds, the heteroatom might be

Answer 8

O, N or S.

Question 9

Ionic bond is formed by elements having:

Answer 9

↓ polarizing power ↓ polarizability

Question 10

What is the value of second electron affinity of oxygen?

Answer 10

+780 KJ/mol

Question 11

The heat of hydration of alkaline earth metals ____ down the group.

Answer 11

Decreases
The charge density of alkaline earth metals decreases down the group. Therefore the attraction of ions and water is decreased i.e. heat of hydration decreases.

Question 12

Li lies at the top of electrochemical series due to:

Answer 12

High hydration energy

Question 13

trend of ionization energy in periodic table

Answer 13

I.E:- ↑ along period, ↓ down the group
Trend along period: GI < GII > GIII < GIV < GV > GVI < GVII < GVIII

Question 14

The oxides of beryllium are

Answer 14

amphoteric

Question 15

which oxides are amphoteric in nature and why

Answer 15

Oxides of relatively less electropositive elements such as Be, Al, Bi and Zn are amphoteric in nature.

Question 16

Lithium combines with nitrogen directly to form

Answer 16

lithium nitrides
Li3N
red pink color

Question 17

What is the symbol of the element with only 5 electrons and 5 protons?

Answer 17

boron

Question 18

why do we call group 2 elements alkaline earth metals

Answer 18

(i). They give alkalis in water.
(ii). Exist abundantly on earth crust in form of carbonates and silicates

Question 19

f-block elements are also called

Answer 19

Inner transition elements

The f-block elements are the lanthanides and actinides and are called the inner transition elements because of their placement in the periodic table due to their electron configurations.
In these elements, three outermost shells are not completely filled. The last electron in them enters in the (n-2) subshells.

Question 20

After hydrogen and helium, the smallest element in the periodic table is?

Answer 20

Flourine

Question 21

Most important commercial source of lithium is

Answer 21

Spodumene is LiAl(SiO₃)₂(Lithium aluminium silicate)

Question 22

The property which increases upto group IV-A then decreases onwards

Answer 22

mp and bp

Question 23

The milk of magnesia MgOH2 is used for the treatment of

Answer 23

acidity

Question 24

Most electropositive element of the periodic table is

Answer 24

Cs

Question 25

In second period of periodic table, number of elements belong to “p” block are

Answer 25

6

Question 26

Carbonate of ________ is least soluble in IA group.

Answer 26

lithium

Question 27

Sodium metal cannot be stored under

Answer 27

polar solvents like alcohol
Na metal is very reactive so it is stored in non-polar solvent like hexane, benzene and kerosene.

Question 28

trend of electrical conductance

Answer 28

Electrical conductance increases from IA to IIIA.

Question 29

Caustic Soda is

Answer 29

Deliquescent

Question 30

What is the electronic configuration of Cs?

Answer 30

[Xe] 6s1

Question 31

the hydrides of Be and Mg are classified as intermediate hydrides. their behavior is :

Answer 31

polymeric and covalent in nature

Question 32

potassium is found in nature as carnalites its composition is

Answer 32

KCl.MgCl2.6H2O

Question 33

calcium is found in nature as CaSO4(2H2O). this is commercially called

Answer 33

gypsum

Question 34

fajans rule states that small highly charged ions tend to form more:

Answer 34

covalent compounds

Question 35

reason for alkali metals to be soft is that

Answer 35

there is only one valency

Question 36

which oxide sodium predominantly forms in oxygen

Answer 36

Na2O2 (pale yellow)
sodium peroxide

Question 37

molecular formula of silica

Answer 37

SiO2

Question 38

sodium carbonate when fused with sand forms sodium silicate which is commonly known as

Answer 38

water glass

Question 39

when Pb shows inert pair effect it always form

Answer 39

ionic bond

Question 40

electron affinity trend

Answer 40

First electron affinity is mostly exothermic while second electron affinity is usually endothermic.
Additional Information:
E.A in groups:
I > II < III < IV > V < VI < VII > VIII
e.g. Na > Mg < Al < Si > P < S < Cl > Ar