Answer:
a) Let the %age of 63u Cu be x %
%age of 65u Cu = 100-x %
Average atomic mass = 63.5 = x/100 × 63 + 100-×/100 × 65
63.5 = 63x/100 + 65 - 65x/100 = -2×/100 +65
-1.5 = -2×/100
× = 150/ 2 = 75%
So , 63 u Cu is 75% and other is 25%
b) each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.
3) Each element within a group has similar physical or chemical properties because of its atom's outermost electron shell (most chemical properties are dominated by the orbital location of the outermost electron)
4) In chemistry and physics, a valence electron is an outer shell electron that is associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair
6) For starters, metal elements have high electrical conductivity properties. ... Metal elements are also malleable and ductile, allowing them to be “worked.” Nonmetal elements have poor electrical, as well as thermal, conductivity. They aren't able to pass electricity or heat as well as metal elements.
