Answer:
( B) They all have their valence electrons in the same type of subshell.
Explanation:
With each period, a new shell is added to the atom.
Further, the groups are classified based on the type of subshell the last electron enters and number of valence electrons.
For all elements of same group, the last electron enters the same type of subshell.
Say, for group 1, last electron enters s orbital and they have 1 valence elctron.
for group 17, last electron enters p orbital and they have 7 valence electrons.
(A) and (D) are wrong because, energy level of the valence electrons is determined by the principle quantum number n and l and not by the type of subshell(only l) they enter.
(C) if the valence electron enters p orbital, then the elements will be placed in the p- block.
Answer:
Water heats and cools more slowly than landmasses.
Explanation:
because the coastal regions will stay cooler in summer and warmer in winter but creating a more moderate climate with a narrower temperature range.
Atomic weight of a Platinum:
195.078 u = 195.078 * 1.66 * 10^(-27) kg = 3.2382948 * 10^(-25) kg
m ( Pt ) = 3.2382948 * 10^(-25) * 5.35 * 10^(21) =
= 1.732488 * 10^(-3) kg = 1.732448 g
The initial sample has a molecular formula of MnSO₄·H₂O. This molecule is a hydrate as it has a unit of water within its structure for every molecule of MnSO₄. This sample is being dehydrated to remove the water to give.
MnSO₄·H₂O → MnSO₄ + H₂O
MnSO₄·H₂O has a molecular mass of 169.02 g/mol. While MnSO₄ has a molecular mass of 151 g/mol. Water has a molecular mass of 18.02 g/mol. We now can use the ratio of the mass of water to the mass of the initial sample to determine the percentage of each component by mass.
% water by mass:
18.02/169.02 x 100% = 10.7% Water by mass.
% MnO₄ by mass:
151/169.02 x 100% = 89.3% MnSO₄ by mass.
Water makes up 10.7% of the initial mass of MnSO₄·H₂O.
