The number of electrons in an atom's outermost valence shell governs its bonding behaviour. Elements whose atoms have the same number of valence electrons are grouped together in the Periodic Table. ... Nonmetals tend to attract additional valence electrons to form either ionic or covalent bonds.
Explanation:
According to the analysis, Molarity is amount mole per volume(1L). the amount in mole would be molarity × volume in litres.
0.500M × (250/1000)L= 0.125moles.
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What happens is that the sodium solution when put in water reacts and creates thermal energy .