# AP Chemistry : Other Atomic Concepts

## Example Questions

### Example Question #1 : Elements, Ions, And Isotopes

As atomic radius decreases, the force of attraction between the nucleus of the atom and its electrons __________.

decreases

cannot be determined

stays the same

increases

increases

Explanation:

As the atomic radius decreases, electrons are drawn closer to the nucleus. Since the electromagnetic force between the positively charged nucleus and negatively charged electrons is a function of distance, the force of attraction, or effective nuclear charge, exerted on each electron will be greater.

### Example Question #1 : Other Atomic Concepts

What is the shorthand electron configuration for gallium?

Explanation:

To write out the shorthand electronic configuration for Ga, you simply write down the noble gas that that comes before , in this case , then write the rest of the electron configuration as normal.

### Example Question #1 : Elements, Ions, And Isotopes

An electron falling to a lower energy level gives off a blue glow (λ=475nm). How much energy is emitted?

4.184 x 10-19 J

Energy is not emitted

3.14x10-37J

3.14x10-40J

4.184 x 10-17 J

4.184 x 10-19 J

Explanation:

E=hf, or E=hc/λ

h is Planck's constant with a value of 6.62606957 × 10-34 m2 kg / s. Converting 475nm to m gives 4.75x10-7m. c is the speed of light with 3x108m/s. Putting these variables into the second equation you get 4.174x10-19J

### Example Question #1 : Elements, Ions, And Isotopes

The atomic number of an atom is equal to the number of __________.

neutrons

protons

protons + neutrons

electrons + neutrons

electrons