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.
Combustible: Charcoal, straw, cardboard, paper, candle, wood.
Non-combustible: Chalk, stone, iron rod, copper coin, glass.
The mole fraction of solute in a 3.87 m aqueous solution is 0.0697
<h3>
calculation</h3>
molality = moles of the solute/Kg of the solvent
3.87 m dissolve in 1 Kg of water= 1000g
find the moles of water= mass/molar mass
that is 1000 g/ 18 g/mol= 55.56 moles
mole of solute = 3.87 moles
mole fraction is = moles of solute/moles of solvent
that is 3.87/ 55.56 = 0.0697
The term "solution" is more frequently used when a homogeneous mixture<span> is a liquid, although it is sometimes used if the </span>homogeneous mixture<span> is a gas.</span>
