Remember that a cation will be smaller than its neutral atom, and an anion will be larger than its neutral atom. This would automatically eliminate answer choices A and D.
Also keep in mind that atomic radii decreases from left to right as you move along a periodic table. It also decreases from bottom up.
Atomic radii increases as you move from right to left and as you go from up to down.
As bromine is higher up in the periodic table than Iodine, it would have a smaller radius. Iodine would have a larger radius.
The correct answer is B. Br
They both have two electron shells. Period indicates number of shells.
Answer:
a) 
is the mass of 1 mole of bricks.
b) 
moles of bricks have a mass equal to the mass of the Earth.
Explanation:
a) Mass of brick = 4.0 kg
1 mole = 
particles/ atoms/molecules
Mass of 
bricks :
is the mass of 1 mole of bricks.
b)
Mass of the Earth = M = 
Mass of 1 mole of brick = m=
Let the moles of brick with equal mass of the Earth be x.
moles of bricks have a mass equal to the mass of the Earth.
In an acid and base neutralization reaction, the products are salt and water.
the first law says that the change in internal energy of a system is given by:
δ<span>E = δq + δw</span>
where δ<span>E is the i change in internal energy, </span>
<span>δq is the amount of thermal energy added to the system from the surroundings </span>
<span>δw is the l work done *on* the system *by* the surroundings. </span>
<span>For a system only undergoing expansion work,
δw = -p</span>δ<span>V, so: </span>
δE = δq - p δ<span>V </span>
when δV = 0, then δe=δq
