Q.1 – What is the significance of: i. Atomic Number.ii. Atomic Mass Number.

Answer:i. Atomic Number – Denotes number of

electrons & protons.

ii. Atomic Mass – Denotes number of

nucleons.

1. Matter has mass and takes up space.

2. Atoms are basic building blocks of matter, and cannot be chemically subdivided by ordinary means.

3. Even though an atom is really small, it is made of even smaller particles.

4. It’s made of 3 tiny subatomic particles:

i. Protons.

ii. Neutrons.

iii. Electrons.

• A substance composed of a single kind of atom.

• Cannot be broken down into another substance by chemical or physical means.

• Smallest part of an element is an ATOM.

• Example: Hydrogen, Carbon, Sodium, Magnesium etc.,.

• A substance in which two or more different elements are CHEMICALLY bonded together.

• Example: Water, Ammonia, Methane, Carbon Dioxide etc.,.

• Two or more substances that are mixed togetherbut are NOT chemically bonded.

• Example: Air, Water in Oil, Ice in Water etc.,.

• The number of protons found in the nucleus of an atom.

OR

• The number of electronssurrounding the nucleus of an atom.

• An abbreviation of the element name.

• The number of protons and neutrons in the nucleus of an atom.

• Number of PROTONS = ATOMIC NUMBER

• Number of ELECTRONS = ATOMIC NUMBER

• Number of NEUTRONS = ATOMIC MASS – ATOMIC NUMBER

• In 1869, Dmitri Ivanovitch Mendeléev created the firstaccepted version of the periodic table.

• He grouped elements according to their atomic mass, and as he did, he found that the families had similar chemical properties.

• THE PHYSICAL AND CHEMICAL PROPERTIES OF ELEMENTS ARE PERIODIC FUNCTION OF THEIR ATOMIC MASSES.

• Blank spaces were left open to add the new elementshe predicted would occur (& to maintain periodicity).

• As a result, he was able to classify 63 elements known at that time.

• Henry Moseley, in 1913, showed that the frequency of X-Ray emitted by an element is related to its Atomic Number (Z).

• Thus, he modified the periodic law given by Mendeléev.

• THE PHYSICAL AND CHEMICAL PROPERTIES OF ELEMENTS ARE A PERIODIC FUNCTION OF THEIR ATOMIC NUMBERS.

• Long form or the modern period table consists of 118 elements spread across:

i. 7 horizontal rows called as PERIODS (numbered 1 to 7).

ii. 18 vertical columns called as GROUPS (numbered 1 to 18).

• Below the main table are placed two series (Lanthanides & Actinides) containing fourteen elements each.

• Furthermore, it is divided into 4 blocks.

• Group 1 & 2 -> S block.

• Group 3 to 12 -> D block.

• Group 13 to 18 -> P block.

• Two series placed @ bottom -> F block.

• Metals are good conductors of heat and electricity.

• Metals are shiny.

• Metals are ductile (can be stretched into thin wires).

• Metals are malleable (can be pounded into thin sheets).

• A chemical property of metal is its reaction with water which results in corrosion.

• Non-metals are poor conductors of heatand electricity.

• Non-metals are not ductile or malleable.

• Solid non-metals are brittle and break easily.

• They are dull.

• Many non-metals are gases.

Sulfur

• Metalloids (metal-like) have properties of both metals and non-metals.

• They are solids that can be shiny or dull.

• They conduct heat and electricity better than non-metals but not as well as metals.

• They are ductile and malleable.

SILICON

• Happy Heman Likes Beer But Could Not Obtain it for Free isiliye NeeNa se Maanga, AlSi Paise so She Called Arjun KaCa

• Elements covered = H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca.

B2p1

1IA

18VIIIA

12

IIA13

IIIA14

IVA15VA

16VIA

17VIIA

2

33

IIIB4

IVB5

VB6

VIB7

VIIB8 9

VIIIB10 11

IB12IIB

4

5

6

7

H

1s1

Li

2s1

Na

3s1

K

4s1

Rb

5s1

Cs

6s1

Fr

7s1

Be

2s2

Mg

3s2

Ca

4s2

Sr

5s2

Ba

6s2

Ra

7s2

Sc

3d1

Ti

3d2

V

3d3

Cr

4s13d5

Mn

3d5

Fe

3d6

Co

3d7

Ni

3d8

Zn

3d10Cu

4s13d10

B

2p1

C

2p2

N

2p3

O

2p4

F

2p5

Ne

2p6

He

1s2

Al

3p1

Ga

4p1

In

5p1

Tl

6p1

Si

3p2

Ge

4p2

Sn

5p2

Pb

6p2

P

3p3

As

4p3

Sb

5p3

Bi

6p3

S

3p4

Se

4p4

Te

5p4

Po

6p4

Cl

3p5

Be

4p5

I

5p5

At

6p5

Ar

3p6

Kr

4p6

Xe

5p6

Rn

6p6

Y

4d1

La

5d1

Ac

6d1

Cd

4d10

Hg

5d10

Ag5s14d10

Au6s15d10

Zr

4d2

Hf

5d2

Rf

6d2

Nb

4d3

Ta

5d3

Db

6d3

Mo

5s14d5

W

6s15d5

Sg

7s16d5

Tc

4d5

Re

5d5

Bh

6d5

Ru

4d6

Os

5d6

Hs

6d6

Rh

4d7

Ir

5d7

Mt

6d7

Ni

4d8

Ni

5d8

1. Trends in the MPT.

“It is not the answer that enlightens, but the question.”

- Eugene Ionesco