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:
32.6 %
Explanation:
Given data
- Mass of sucrose (solute): 22.8 grams
- Mass of water (solvent): 47.1 grams
Step 1: Calculate the mass of the solution
The mass of the solution is equal to the sum of the mass of the solute and the mass of the solvent.
m(solution) = m(solute) + m(solvent)
m(solution) = 22.8 g + 47.1 g
m(solution) = 69.9 g
Step 2: Calculate the percent-by-mass of sucrose in the solution
We will use the following expression.
Answer: B:
Explanation:
This is the most reasonable answer
In this question, the sulfur atom has atomic number 16 and atomic mass 33. The Atomic number represents the number of the proton inside the atoms and atomic mass represent the mass of the atoms. Since electron mass to small, the atomic mass can be interpreted as the sum of neutron and proton. Then, the number of the neutron would be:
mass= neutron + proton
33= neutron+16
neutron = 17
Answer: 225 joules.
Explanation:
If this a one dimension problem, this is the motion is in the same direction of the force, the equation for work is:
Work = distance × force
⇒ Work = 15 m × 15 N = 225 joules.
This is a special case of the general equation
Work = |F| |displacement| cosine (angle between the force and displacement)
When force and displacement are in the same direction, the angle is 0, so cos(0) = 1. This is the two vectors are parellel and the work is just the product of the two magnitudes (force and distance)
