Answer:
38
Explanation:
Symbol: Sr
Atomic mass: 87.62 u
Electrons per shell: 2,8,18,8,2
Atomic number: 38
Electron configuration: [Kr] 5s2
Van der Waals radius: 255 pm
Valence electrons: two
The density of the stone is 5 because the formula is mass/volume and the volume is 5 and the mass is 25
The electromagnetic spectrum consists of the full range of known electromagnetic waves. And among them, X-rays has the wavelength of the region 1*10-11 to 1*10-8 meters.
