Answer:
26.981539 u
Atomic number: 13
Symbol: Al
Electron configuration: [Ne] 3s²3p¹
The Nobel gasses
Excluding those, the most active are the lower left and upper right.So the least
active (EXCLUDING GROUP 18) are the non- metals furthest form the upper right
De Broglie's equation is used to show that photons have both particle and wave nature. photons are quantized packets of energy. the wave nature of photons can be proven as they have a wavelength. the particle nature is given by them having both velocity and mass.
de Broglies equation is;
λ = h / p
where λ - wavelength
h - Planck's constant
p - momentum
substituting the values in the equation
p = h/λ

p = 2.20 x 10⁻²⁷ kgm/s
momentum of photon is 2.20 x 10⁻²⁷ kgm/s
Answer:
17
Explanation:
since the no. of protons=9
therefore mass no.= 9+8=17