Beryllium
Be
Research
The atomic number is 4, the mass number is 9.012, the period number is 2, and the group number is also 2. The name of the group is Alkali Earth Metals, and it's state of matter is solid, this element is also a metal.
X-rays
Beryllium is relatively transparent to X-rays so ultra-thin beryllium foil is finding use in X-ray lithography.
Structure Materials
Beryllium alloys are used as structural materials for high-speed aircraft, missiles, spacecraft and communication satellites
Nuclear Reactors
Beryllium is also used in nuclear reactors as a reflector or moderator of neutrons.