Answer:
The vertical columns are called groups.
Explanation:
Periodic table consist of vertical columns and horizontal rows.
Vertical columns are called groups while horizontal rows are called periods.
There are seven periods and 18 groups in periodic table.
The elements in same group have similar properties and can react in a similar way.
The elements in same group have same number of valance electrons that's why their reactivity is same.
Consider the example of alkaline earth metals. They are present in group two and have same number of valance electrons (two valance electrons).
They react with oxygen and form oxide.
2Ba + O₂ → 2BaO
2Mg + O₂ → 2MgO
2Ca + O₂ → 2CaO
this oxide form hydroxide when react with water,
BaO + H₂O → Ba(OH)₂
MgO + H₂O → Mg(OH)₂
CaO + H₂O → Ca(OH)₂
With sulfur,
Mg + S → MgS
Ca + S → CaS
Ba + S → BaS
Answer:
c
Explanation:
because the fire gives off radiation
Polar molecules exhibit an unequal balance of charges between the individual elements of the compound. This is brought about by the large difference in their electronegativities. The H atom has the least amount of electronegativity. Then, it is a known periodic trend, that as you go downwards in a group, electronegativity decreases, and increase as you go from left to right. Thus, you can deduce that the most electronegative elements are found in the upper right corner which includes O, N and F atoms. Any bond created between Hydrogen and any of O, N and F atoms is a polar bond.