<span>Answer:
Some metals have the ability to form differently charged ions. For example, iron can form
2
+
or
3
+
ions. If you simply gave the name iron chloride, you would not know which charge the iron ion possessed.
A Roman numeral is to indicate the charge of the iron.
Iron (
II
) means the iron has a
2
+
charge
Iron (
III
) means that the iron has a
3
+
charge
So, iron (
II
) oxide would have a chemical formula of
FeO
.
(The oxide ion has a
2
â’
charge to balance the
2
+
of the iron to form a neutral compound.)
Iron (
III
) oxide would have a chemical formula of
Fe
2
O
3
(Here you need to find the common multiple of 6, so two iron ions with a
3
+
charge will balance the charge of three oxide ions with a
2
+
charge.)</span>
Answer:
Magnetism is believed to be caused by the alignment of small, numerous sub-units called : <em><u>Domains</u></em>
<em><u></u></em>
Explanation:
Domains : A magnetic domain is the region in which in which magnetic field of the atoms are grouped together and aligned.
- In unmagnetized material all the magnetic Domains point in different direction.
- In magnetised material (ferromagnets , antiferromagnets) , The Domains point in a particular( fixed Pattern) direction.
Explanation:
<em>When the electron changes levels, it decreases energy and the atom emits photons. The photon is emitted with the electron moving from a higher energy level to a lower energy level. The energy of the photon is the exact energy that is lost by the electron moving to its lower energy level.</em>
