What are the melting points of each of the rare earth elements? Using this information, determine whether they would occur as a solid, liquid, or gas in nature.
a) Melting points range from 650°C to 3400°C; they occur as solids at room temperature
b) Melting points range from 20°C to 100°C; they occur as liquids at room temperature
c) Melting points range from -50°C to 200°C; they occur as gases at room temperature
d) Melting points range from 1000°C to 5000°C; they occur as solids at room temperature