periodic table - comment on position of lanthanoides and actinoides?

Question

in about 60-80 words .... thanx

Answer 1

The lanthanide (or lanthanoid) series comprises the 15 elements with atomic numbers 57 through 71, from lanthanum to lutetium. All lanthanides are f-block elements, corresponding to the filling of the 4f electron shell, except for lutetium which is a d-block lanthanide. The lanthanide series is named after lanthanum. Most lanthanides are widely used in lasers. These elements deflect UV and Infrared electromagnetic radiation and are commonly used in the production of sunglass lenses.
They are shiny and silvery-white, and tarnish easily when exposed to air. Many are used to make steel. They react violently with most nonmetals. They are relatively soft but their hardness increases with their atomic number. Lanthanides burn in air. They have high melting and boiling points.

The actinides display less similarity in their chemical properties than the lanthanide series, for instance exhibiting a wider range of oxidation states, which initially led to confusion as to whether actinium, thorium, and uranium should be considered d-block elements. All actinides are radioactive.
Only thorium and uranium occur naturally in the earth's crust in anything more than trace quantities. Neptunium and Plutonium have been known to show up naturally in trace amounts in uranium ores as a result of decay or bombardment. The remaining actinides were discovered in nuclear fallout, or were synthesized in particle colliders. The latter half of the series possess exceedingly short half-lives.

Good luck!

Answer 2

They're under the rest of the table, otherwise they'd stretch it out too far and make it unweildy.

(Just add a few the's and and's, you can stretch it out to 80 words.)

Answer 3

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