The least reactive elements are the noble gases since they have a full valence shell and thus require a lot of energy in order to form bonds.
For metals, reactivity increases as you move down a group and as you move leftward within a period.
The trend within a period is due to the increase in ionization energy caused by the decrease in electrons needed to be lost in order for an element achieve a full valence electron shell. The trend within a group is due to the valence shell being further away from the nucleus, resulting in less attractive forces and thus less energy needed for reaction.
For nonmetals, the trends are reversed. Reactivity as you move up a group and as you move rightward within a period.
As you move up a group, the element increases in electromagnetism and thus increasing its reactivity. As you move across a period, there is less electrons needed to be received in order for the element to achieve a full valence shell
hope this helps hun
B. Nanoscale
Because Nano- mean small and you’re measuring something on a ‘scale’
Answer:
d. The limiting reactant is Br2, and 0.13 mol Al should remain unreacted.
Explanation:
From the reaction, 2Al(s) + 3Br2(l) → 2AlBr3(s)
2 moles of Al combines with 3 moles of Br to form 2 moles of AlBr3
Hence 1 mole of Br combines with 2/3 moles of Al
or 0.4 moles of Br combines with 2/3×0.4 moles of Al or 0.267 Moles of Al leaving
0.4 - 0.267 = 0.133 moles of Al remaining unreacted
Answer:
25 cm3 of 0.15 mol dm-3 hydrogen peroxide
Explanation:
Not 100% with this one was a bit tricky.
Answer:
325mg of Aspririn
Explanation:
First you should note the information that the problem gives you:
- The bottle of Aspirin has 5gr (grains)
- 1gr(grain) = 65mg (miligrams)
Also, the problem is asking about how many aspirin are in 5 gr (grains), so you should use a conversion factor, as follows:
-First you should put the quantity you need to convert:
-Then you write the denominator of the conversion factor that must have the same units that you want to convert, in this case gr:
-Then you write the numerator with the units that you want to obtain and the numerical equivalence between the units, in this case:
-Finally you multiply numerators and divide by denominators:
