All the members of a family of elements have the same number of valence electrons and similar chemical properties. The horizontal rows on the periodic table are called periods.
Answer:
Dmitri Mendeleev and Henry Moseley developed their periodic tables about forty years apart. During that time, many discoveries in chemistry were made.
<span>Percentage
by mass is the amount in mass of a component in a mixture per 100 unit of
mass of the total mixture. Percentage by mass is the same as %w/w.
We can determine this by dividing the mass of the solute with the total mass of
the mixture. From the problem statement, the mass of the component is given as 2 g and the mass of the total mixture is 10 milliliter. It would be difficult to express this in percent by mass since we do not have data in the density. We can only express this in percent by w/v which is grams per 100mL of solution.
%w/v = 2 g / 10mL x 100 = 20% w/v solution</span>
Technically, with the right conditions and catalyst(s), all of the metals will react with water to form a metal hydroxide and hydrogen gas. However, at room temperature and atmospheric pressure, lithium is the only metal that will undergo the reaction to a significant extent.
