What is the magnitude of the gravitational force between the earth and a 1 kg object on its surface? (Mass of the earth is 6 × \(10^{24}\) kg and radius of the earth is 6.4 × \(10^6\) m.)
9
-
10
16
32
Sulphur
24
12
2
1
0
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.