What part of an atom determines it's chemical properties?
Electrons determine an atoms chemical properties. Protons and neutrons are in the nucleus. The number of protons determines the number of electrons and so are indirectly involved.
Atom-the smallest particle of an element that still has all the properties of that element That is correct, but if you want it in more detail: An atom is the smallest fragment of a chemical element which retains the properties of that element and can take part in chemical rections. Hope this helps :)
When neutrons fired on the atoms of element neutrons become part of the nucleus of atom so what effect does the presence of an extra neutrons have on the chemical properties of new atom formed?
The addition of neutrons to the nucleus of an atom creates a new isotope of the element. It changes the nuclear properties of the atom, but has no effect on its chemical properties. Chemical reactions occur as the result of interactions between the electrons of atoms, not their nucleii so, for example, Carbon-12 and Carbon 14 will react chemically in exactly the same ways. The resulting compounds will have identical chemical properties but different molecular…