An element is a substance made from only one type of atom (e.g. oxygen is an element made up of only oxygen atoms).
An atom is the simplest form of an element that can exist, such as a lithium atom (Li).
Atoms of different elements can be combined together to create compounds, e.g sodium oxide (Na2O).
A molecule is a combination of 2 or more atoms that form chemical bonds. When these atoms are of the same element, they can be called molecules (e.g. O3 - ozone).
However when a molecule is made up of atoms of different elements, they are classified as compounds (e.g. CO2 - carbon dioxide).
So all compounds are molecules, but not all molecules are compounds.
The first two ionization energy of nickel are expressed as:
Ni(g) = Ni^+(g) + e^- Ni^+(g) = Ni^2+(g) + e^-
IOnization energy os the energy that is neccessary in order to remove one mole of electrons from an atom.
Hope this helps.
Answer:
It goes the crust mantle outer core and inner core. The crust is what we are standing on it has dirt, rock, stone, the mantle it has lots of silicate rocks and magnesium. The outer core has liquid nickel and iron and the inner core has solid metals
The oxd state of O is -2
the oxidation state, of O2 is(-2)2
the oxd state of Se will be +4
the oxd state of compound will be zero
