Periodic classification

chemistry

mnemonic of f block actinoid

thapa u nappu

aam kam bikay

cafe aise farmao madam nashtha lao

Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

atomic number of starting and ending of

• d block

• f block

• p block

C

C

A

1. Number of electrons filled in 4th period

2. number of electrons that can be filled in 4th shell

1. number of electrons or elements in given period= 2,8,8,18,18,32,32

2. number of electrons in a shell= 2n²

general electronic configuration of d block

ns^0-2 n-1d^1-10

general electronic configuration of p block

ns² np^1-6

D

diagonal relation dekhte time Be, Boron carbon ko ek saath lo, d block beech me mat lo

In nomenclature of elements after 100, suffixes used are for numbers

everything same just remember quad for four and sept for seven

pnemonic for elements after 100

Modi ka number lahore ke refugee ne dubai sea ke bahar 

has mat das rang ka konsa nhi flower

mc lover tussi ogod

how to find group number of actinoids, lanthanoids and atomic numbers after 104

How to find group number after atomic number Z=12

why position of helium in p block is justified

Strictly helium belongs in the s block but its position in p block is valid because it has completely filled valence shell ns² and as a result exhibit characteristic properties of noble gases

Why hydrogen is placed separately at the top of periodic table

Because it has one electron it can be placed in group 1 but it can also gain an electron to achieve noble gas configuration and act as halogen so can be placed in group 17. So it is placed separately

how metallic character and reactivity changes down the group in s block.

metallic character and reactivity increases down the group in s block

reactivity is high thats why s block is never found in pure form in nature

what are the exceptions of s block compounds which are predominantly ionic

s block element compounds are predominantly ionic except lithium and berilium

Metals or non metals which are liquid at slightly high temp or room temp

Cs and Ga are liquids at slightly high temp

Hg is liquid at room temp

non metal bromine is liquid at room temp

exceptions of s block elements

hydrogen and helium

A

A

dobereiner triad method and examples

said that atomic weight of middle element is the arithmetic mean of other two elements

examples

Li Na K

Cl Br I

Ca Sr Ba

Who was first scientist who related properties of elements with atomic mass

Newlands law of octaves

what was newlands law of octaves and why did it fail

if we arrange elements in acc to atomic mass then every 8th element will have same property as 1st element

it was only valid upto calcium and failed after discovery of inert gas

mendeleevs periodic law statement and drawbacks

It stated that physical and chemical properties of elements are periodic functions of their atomic masses

drawbacks

no place for isotopes

no separate place for hydrogen

in some places, element having higher atomic mass was placed before lower atomic mass

moseleys experiment benefits

It challenged mendeleevs periodic law

and basis of modern periodic table

what was moseleys experiment

1. He bombarded electrons on metal surfaces and obtained x rays

2. he observes that the frequency of x rays was in relation with atomic number of metal used

3. root of frequency= a(Z-b) a and b are constant. So root of frequency is proportional to atomic number Z

exception in alkaline earth metals

Beryllium is not included in alkaline earth metals

because it does not form alkaline hydroxide or oxide, its oxide is amphoteric

What are transurenic or transurenium elements

elements after atomic number 92 uranium

they are man made synthetic and not known in nature

what are representative or main group elements

elements of s and p block

what is period number of 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶4d¹⁰

acc to electronic configuration 4th period

but it is in 5th period

it is palladium

atomic no. 46

penetration effect and shielding effect order

s>p>d>f

across a period, effective nuclear charge

increases

D

successive ionisation enthalpy increase

for same element, order of vanderwall, covalent and metallic radius

Vanderwall> metallic> covalent

VMC

vanderwall almost double of covalent

Trend in size for elements in s block

E banao aur N banao

atomic size order for cations in s block

everything same like normal except Li>Mg

Li+ greater or equal to Mg2+ in cationic form

size order in p block

in 13th group B<Ga<Al<In<Tl

Al>Ga because of transition contraction

rest groups are normal khushiyon ka pitara

how does size of element depend on oxidation number

size of oxygen in water and OF2 is not same because of oxidation number

-ve oxidation number means larger atom

A

D

• Neon (Ne):

  Has the highest second ionization energy because its first ionization energy is to remove an electron from its outermost shell, making it much higher than the first ionization energy of the other elements, and removing a second electron is extremely difficult. 

• Lithium (Li):

  Has the lowest second ionization energy because after losing its single valence electron, it achieves a noble gas configuration, making it very easy to remove a second core electron.