The elements that have the same valence are, mainly, in the same principal groups (principal columns) of the periodic table.
The principal columns are 1, 2, 13, 14, 15, 16, 17 and 18.
For example:
1) the elements with valence 1+ are in the first column:H, Li, Na, K, Rb, Cs, Fr.
2) The elements with valence 2+ are in the second column: Be, Mg, Ca, Sr, Ba, Ra.
3) The elements with valence 2- are in the column 16: O, S, Se, Te, Pb
But also those elements may have other valences: S, Se and Te, have also valences 2, 4 and 6. And Pb have valences 2 and 4.
4) The elements with valences 1-, 1, 3, 5 and 7 are in the column 17: Cl, Br, I, At.
F, the first element of group 16, has valence 1- and 1+
Answer:
false
Explanation
The chemical bonds were broken when creating the compound MgO.
Answer : The new volume of the balloon is, 22.4 L
Explanation :
Charles' Law : It is defined as the volume of gas is directly proportional to the temperature of the gas at constant pressure and number of moles.
or,
where,
= initial volume of gas = 22.6 L
= final volume of gas = ?
= initial temperature of gas = 
= final temperature of gas = 
Now put all the given values in the above formula, we get the final volume of the gas.
Therefore, the new volume of the balloon is, 22.4 L
(4) titration, the process of using an aqueous solution of known concentration to determine the concentration of another solution of unknown concentration, is your answer.
