Question

explain how lanthanaides ionic radius decrease with increasing atomic number​

Answer 1

Answer:

Lanthanide ionic radius decrease with increase in atomic number.

Explanation:

On moving from 5th to 6th period,there occur 14 lanthanide element in which last electron enter into (n-2)f-subshell .Since the screening power of electron is very poor and shielding is not effective,the attraction force on the outer electron increase as a result of which ionic radius decrease.

Answer 2

Question -

Explain how lanthanaides ionic radius decrease with increasing atomic number?

Answer:-

☞ The effect results from poor shielding of nuclear charge (nuclear attractive force on electrons) by 4f electrons; the 6s electrons are drawn towards the nucleus, thus resulting in a smaller atomic radius.Thus the shielding effect is less able to counter the decrease in radius caused by increasing nuclear charge.

⏩ More to know:-

• The lanthanide contraction is the greater-than-expected decrease in ionic radii of the elements in the lanthanide series from atomic number 57, lanthanum, to 71, lutetium, which results in smaller than otherwise expected ionic radii for the subsequent elements starting with 72, hafnium.
• The term was coined by the Norwegian geochemist Victor Goldschmidt in his series "Geochemische Verteilungsgesetze der Elemente".

Hope its helpful....!!

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