Periodic Classification of Elements II

Question 1

wha are typical elements

Answer 1

)
3rd period elements (Na, Mg, Al, Si, P, S, Cl) except inert gases are called typical elements because
they represent the properties of other element of their respective group.

Question 2

what are transuranic elemnsts

Answer 2

Elements having atomic number more than 92 are known as transuranic element.
All transuranic elements are radioactive & artificial.

Question 3

what is 1st man made lement

Answer 3

technetium

Question 4

what is the only man made lanthanide

Answer 4

promethium(Pm)
All actinoids are radioactive. All lanthanoids are not artificial / man made (except Pm)

Question 5

grp having
(i) mose electro+ve elements
(ii) most electro-ve elements
(iii) most gaseous elements
(iv) 0 valency

Answer 5

(i) grp 1
)ii) grp 17

grp1 8( all elements gaseous)

Question 6

In the periodic table
Number of Gaseous elements
Number of Liquid elements

Answer 6

1)– 11 (H, N, O, F, Cl + Noble gases)
2)– 6 (Cs, Fr, Ga, Hg, Br, Uub)
Bromine is the only non-metal which exists in liquid form.
Number of Solid elements – 95 (if discovered elements are 112)

Question 7

which perioid has most gaseous atoms

Answer 7

2nd
N,O,F,Ne

Question 8

which is longest grp

Answer 8

IIIB/3rd group is called longest group having 32 elements including 14 Lanthanides and 14 Actinides

Question 9

radioactive elements based onplanets

Answer 9

neptunium(Np)
plutonium(Pu)

Question 10

wonder element

Answer 10

titanium

Question 11

most lowet ionisation enthalpy
most highest ionisation enthalpy

Answer 11

caesium
helium

Question 12

what are magic numbers

Answer 12

In the periodic table, elements with similar properties occur at intervals of 2, 8, 8, 18, 18 and 32.
These numbers are called as magic numbers.

Question 13

variationof eff nuclear charge from period

Answer 13

the effective nuclear charge increases due greater atomic number nd more nuclear charge causing e-s to be attracted more

Question 14

varitona or eff uclear chargw down a grp

Answer 14

the eff nuclear charge decreases because size of atom becomes larger due to interelectronic repulsion and the nuclear charge on the outer e-s is less

Question 15

why is thr a drastic increase in the atomic radius of noble gases

Answer 15

because they are measured using van der waals radius

Question 16

exception inatomic radii: boron family

Answer 16

The atomic radii of Gallium is less than aluminium due to poor screening effect of intervening d -orbitals.
atomic orbital of thallium is also less than indium.

Question 17

exception in atomic radii: d-block elemtns in a period

Answer 17

Sc Ti V Cr Mn
The atomic radius decreases as usual, because effectinve nuclear charge is greater than sheilding

Fe Co NI
the atomic radius mostly equal due to effective nuclear charge and shielding effect are almost equal

Cu Zn
the atomic radius increases, because shileding is greater than eff nuclear charge

Question 18

lanthanide contraction

Answer 18

Because of complicated structure of f-orbital and due to poor shielding of f & d electrons, the outermost
shell electrons get highly attracted towards nucleus.
(c) But in lanthanides and actinides, with each electron, nuclear charge increase by +1 so size decreases
slowly, this decrement in size is known as lanthanide contraction.
Here Nuclear charge > Screening effect

one consequence is tht the chemical and physical properties of lanthanides are very similar

Question 19

exception in atomic radius: down a grp

Answer 19

in1,2,3 d-transition elemnt grps, the atomic radius decreases and then equal.
In vertical columns of transition elements there is an
increase in size from 1st member to 2nd member.
*But from 2nd
member to 3rd
member, there is
very small change in
size and in some cases
the sizes are same.

this is applicable except 3rd grp
Sc< Y < La= Ac