Number of valence electrons in \(Cl^–\) ion are:
The average atomic mass of a sample of an element \(X\) is 16.2u. What are the percentages of isotopes \(^{16}X_8\) and \(^{18}X_8\) in the sample?
If bromine atom is available in the form of, say, two isotopes \(^{79}Br_{35}\) (49.7%) and \(^{81} Br_{35}\) (50.3%), calculate the average atomic mass of bromine atom.
Which of the following materials fall in the category of a “pure substance”?
(a) Ice(b) Milk(c) Iron (d) Hydrochloric acid (e) Calcium oxide (f) Mercury (g) Brick (h) Wood (i) Air