each isotope of a given element has a different mass number. For example, carbon-12, carbon-13<span> and carbon-</span>14<span> are </span>three<span> isotopes of the element carbon with mass numbers </span>12<span>, </span>13<span> and </span>14<span> </span>
s - orbitals have a spherical symmetry and the probability of finding an electron in an s orbital is equal for equal distance in x, y or z direction. i mean the probability of lets say an electron found at a distance 10 units from nuclues, its value will be same for x, y and z when u go 10 units distnace from nucleus in these directions. then the value at 5 units would be some value which also would be same for x,y and z.
Easier explanation is that if u place a ball, can u tell towards which axis it is oriented? no, its equally in all directions. So, non- directional.
However, if you have p- orbitals like dumb bells, a dumb bell can be oriented in three different directions, either x or y or z. see the pics.
Answer:
PBr3 - Molecule , Polar
N2H2 - Molecule , (Polar in E- form and Non- polar in Z form)
C2H2 - Molecule , Non- Polar
N2 - Molecule , Polar
NCl3 - Molecule , Polar
SiF4 - Molecule , Non- Polar
NH3 - Molecule , Polar
F - Not- Molecule (atom)
H2 - Molecule and Non- Polar
Explanation:
Molecule : these are group of two or more atoms joined by strong force of attraction.
H2 is non- polar because it is homoatomic molecule.(made up of same element)
N2 is non- polar because it is homoatomic molecule.