Electrons located in the outermost shell of an atom are called valence electrons. The outermost electrons are involved in chemical reactions. The electrons in the outer shell determine the reactivity of the element. For example, potassium (2,8,8,1) has one valence electron.
Group 1A (the alkali metals) almost always form cations (positive ions). They'd need anions (negative ions) to ionic bond with. Beryllium (Be) is group 1A already and forms Be+ cation. Bromine is a halogen, and forms Br-, an anion. Platinum is a metal, and usually won't ionic bond with anything. Francium is rare and highly radioactive, plus it so happens to be group 1A as well. Only bromine can form the anion that the group 1A cations need.
Answer:
D
Explanation:
It depend on your parents genes. What they have, is what you'll have.
~<em>Jack Pullman</em>
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