EVERYDAY SCIENCE

Detailed explanation-1: -Based on the number of valence electrons, the elements are arranged in the periodic table. The outer shell electrons are the valence electrons. These valence electrons are far from the nucleus. In the periodic table across each row or period, the valence electrons increase one by one in group and group .

Detailed explanation-2: -How do you find the valence electrons? For neutral atoms, the number of valence electrons is equal to the atom’s main group number. The main group number for an element can be found from its column on the periodic table. For example, carbon is in group 4 and has 4 valence electrons.

Detailed explanation-3: -In the modern periodic table, the elements are arranged according to their atomic number-not their relative atomic mass . In the periodic table the elements are arranged into: horizontal rows, called periods, in order of increasing atomic number.

Detailed explanation-4: -The presence of valence electrons can determine the element’s chemical properties, such as its valence-whether it may bond with other elements and, if so, how readily and with how many. In this way, a given element’s reactivity is highly dependent upon its electronic configuration.

Detailed explanation-5: -The number of valence electrons in an atom is reflected by its position in the periodic table of the elements (see the periodic table in the Figure below). Across each row, or period, of the periodic table, the number of valence electrons in groups 1–2 and 13–18 increases by one from one element to the next.