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Periodic Properties - Atomic Size

CISCE: Class 10

Definition: Atomic Size (Atomic Radius)

It is the distance between the centre of the nucleus of an atom and its outermost shell.

Maharashtra State Board: Class 10
CISCE: Class 10

Atomic radius is the distance from the nucleus to the outermost shell.
Over time, atomic size decreases due to a stronger nuclear pull.
Down a group, atomic size increases as new shells are added.
Atomic size depends on the number of shells and the nuclear charge.
Cations are smaller, anions are larger, and in isoelectronic ions, size decreases with more protons.

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Atomic radius trend periodic table [00:09:42]

Arrange the following as per the instruction given in the bracket
Na, K, Li (Increasing atomic size)

Arrange the following as per the instruction given in the bracket:

Mg, Cl, Na, S, Si (decreasing order of atomic size).

Give scientific reasons for the following:

Atomic radius goes on decreasing while going from left to right in a period.

Write information about the given atomic numbers in the table. 10, 20, 7.

Write scientific reason.
Atomic radius goes on increasing down a group.

Electropositive nature of the element(s) increases down the group and decreases across the period
Electronegativity of the element decreases down the group and increases across the period
Atomic size increases down the group and decreases across a period (left to right)
Metallic character increases down the group and decreases across a period.

On the basis of the above trends of the Periodic Table, answer the following about the elements with atomic numbers 3 to 9.