Answer:
Elements having same valence electrons are placed in <u>same group.</u>
Explanation:
First, let's start with some basic concepts of modern periodic table:
1. Modern Periodic table : It is the arrangement of element in the increasing order of their atomic numbers
The Modern periodic table is divided into Periods and groups .
Periods : These are the horizontal rows. There are seven periods in the periodic table . Period 1 has 2 element. Period two and three has 8 elements , period 4 and 5 have 18 elements and the period 6 and 7 have 32 elements.
Same period have same number of atomic orbital(Shell)
Group : The group is the vertical columns . There are 18 groups in the modern periodic table.Those element which have same group number will also have same number of electron in their outermost shell. The number of electron in the outermost shell determines the valency of the element.
So, elements showing same valency are placed in same group.
All alkali are place in group 1 and have 1 valance electron in the outermost shell
O2 gas, where there are two Oxygen atoms which are covalently bonded together
<span>the noble gases are those who occupy the eighth group of the periodic table and are so called because having the complete valence shell do not need to form bonds with other atoms and are thus in atomic form ...
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The noble gases (also called rare gases) are of the inert gases that constitute the eighteenth [1] group of the periodic table of the elements, ie, the right-most column. They consist of atoms with electron shells full. It includes the following elements: helium neon argon krypton xenon radon Ununoctium <span>Sometimes they (particularly helium) are located together with other gases (mostly nitrogen and methane) into endogenous sources; helium of endogenous origin comes from the decomposition of radioactive elements present in the subsurface that emit α particles (ie ions He2 +): These oxidized species present in the soil and become elio.I atoms of the noble gases are all monatomic gas, not easily liquefiable, present the atmosphere in different percentages; the most common is argon which is approximately the 0.932%.</span>
