Answer: Ionic radii is half the distance between two ions.
Explanation: from top to bottom down an element group, ionic radius increases. This is because a new electron shell is added as you move down the periodic table.
Might Be wrong not sure :)
Answer:

Explanation:
Let us look at all the answers definitions,
Sponsor would not work as it talks about a company offering you something in back for an advertisement.
Obtain would work as it means to acquire something.
Neglect would not work because it means to fail to care for something properly
Dismiss wouldn't work because it means to leave or allow to exit
Those are called isotopes,
the answer is 3.
each element has its own unique number of protons (atomic number) but a different number of neutrons can be shown in example number 3.
b) It is based on atomic properties as alkali metals requires 7 more electrons to complete their outer orbit. And they try to give those electrons to other elements to obtain noble gas configuration.
Noble gases are the gases which do not react easily with anything. They are also called as Inert gases, and belongs to group 18 of the periodic table.
Alkali metals are the substances which are found in Group I of a periodic table. Mostly the elements which are present are:
Properties of alkali metals are: Soft, shiny reactive metals. They are soft enough to cut with knife. Metals react with water and air quickly and gets tarnish, so pure metals are stored in container by dipping them in oil to prevent oxidation.
To know more about Alkali metals, refer to this link:
brainly.com/question/18153051
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