Answer: There are few simple rules to follow.
(1) The atomic number is equal to the number of protons.
Z
= number of protons
(2) In neutrally charged elements, the number of electrons is the same as the number of protons.
Z
= number of protons = number of electrons (no charge)
Otherwise, positive charge means that the element lost an electron and negative charge means it gained an electron.
(3) The atomic mass is equal to the sum of the number of protons and number of neutrons.
A
= number of protons + number neutrons
or
A
=
Z
+ number neutrons
So if you say that
Z
= 20 and
A
= 40, then
A
=
Z
+ number neutrons
40 = 20 + number of neutrons
40 - 20 = number of neutrons
Therefore,
number of neutrons = 20
Explanation:
The chemical formula for acido perbromico is HBrO4 or perbromic
acid or bromate. It is an inorganic compound and an oxoacid of bromine. When an
H+, the –ate ion is –ic acid: one less O is –ous acid, ttwo less is hypo- -ous
acid and one more is per- -ic acid.
This reaction would give rise to two products.
- 2-bromo-3-methylhexane, and
- 3-bromo-3-methylhexane.
However, 2-bromo-3-methylhexane would be more common than 3-bromo-3-methylhexane among the products.
The hydrogen atom in a hydrogen bromide molecule carries a partial positive charge. It is attracted to the double bond region with a high electron density. The hydrogen-bromine bond breaks when HBr gets too close to a double bond to produces a proton
and a bromide ion
.
The proton would attack the double bond to produce a carbocation. It could attach itself to either the second or the third carbon atom.
Carbocations are unstable and might decompose over time. The first carbocation is more stable than the second for having three alkyl groups- i.e., straight carbon chains- attached to the center of the positive charge. Alkyl groups have stabilizing positive induction effect on positively-charged carbon. The second carbocation has only two, and is therefore not as stable. The first carbocation thus has the greatest chance to react with a bromide ion to produce a stable halocarbon.
Bromide ions are negatively charged. They attach themselves to carbocations at the center of positive charge. Adding a bromide ion to the first carbocation would produce 3-bromo-3-methylhexane whereas adding to the second produces 2-bromo-3-methylhexane.
The <em>most likely</em> product of this reaction is therefore 3-bromo-3-methylhexane.
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