2. Symbol: Yb Atomic Number: 70 Mass: 173.04 g/mol Density: 6.9 g/cm Boiling Point: 1469 K -Ytterbium is used in X-Rays. -Ytterbium can also be used to improve stainless steel.

3. Symbol: U Atomic Number: 92 Mass: 238.0289 g/mol Density: 19.1 g/cm Boiling Point: 4404 K -Uranium is used in the creation of nuclear bombs, along with nuclear power plants.

4. Symbol: La Atomic Number: 57 Mass: 138.905 g/mol Density: 6.162 g/cm Boiling Point: 3137 K -Lanthanum is used in Carbon lighting and movie projectors. -Lanthanum can also be added to steel to increase the malleability.

5. Symbol: Ce Atomic Number: 58 Mass: 140.116 g/mol Density: 6.77 g/cm Boiling Point: 3716 K -Used in the making of aluminum alloys and stainless steel. -Cerium gives glass a golden yellow color.

6. Symbol: Am Atomic Number: 95 Mass: 243 g/mol Density: 12 g/cm Boiling Point: 2880 K -Americium is used in smoke detectors. -Americium is also used in the creation of flat glass.

7. Symbol: Pr Atomic Number: 59 Mass: 140.907 g/mol Density: 6.77 g/cm Boiling Point: 3793 K -Used in the making of cigarette lighters. -Widely used in studio lighting and projectors.

8. Symbol: Dy Atomic Number: 66 Mass: 162.5 g/mol Density: 8.54 g/cm Boiling Point: 2840 K -Used to cool nuclear reactor rods. -Dysprosium is used in the making of laser materials.

9. -Symbol: Ho Atomic Number: 67 Mass: 164.93 g/mol Density: 8.76 g/cm Boiling Point: 2993 K -Holmium is used a red or yellow glass coloring. -Used in jewelry and lasers.