Which option describes a similarity and a difference between isotopes of an element?
a) same atomic number; different number of protons
b) same number of protons; different atomic number
c) same atomic number; different mass number
d) same mass number; different atomic number
e) same number of neutrons; same number of protons

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next

What are the first three quantum numbers for the electrons located in subshell 2s?

Complete each row of the table below by filling in the missing prefix or missing exponent.