The answer is Velocity and potential energy. Kinetic energy is the total energy of a system or an object in motion and requires movement.
Answer:
Carbon, germanium, tin and lead.
Explanation:
The silicon is belong to the carbon family. There are five elements in carbon family carbon, silicon, germanium, tin and lead. These five elements are present in same group i.e group fourteen. The elements present in same group have same number of valance electrons.
For example.
Carbon electronic configuration:
C₆ = [He] 2s² 2p²
Silicon electronic configuration:
Si₁₄ = [Ne] 3s² 3p²
Germanium electronic configuration:
Ge₃₂ = [Ar] 3d¹⁰ 4s² 4p²
Tin electronic configuration:
Sn₅₀ = [Kr] 4d¹⁰ 5s² 5p²
Lead electronic configuration:
Pb₈₂ = [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p²
we can see that in case of all elements there are four valance electrons, which are equal to the valance electrons of silicon.
Answer:

Explanation:
The Rydberg equation gives the wavelength λ for the transitions:

where
R= the Rydberg constant (1.0974 ×10⁷ m⁻¹) and

Data:

λ = 657 nm
Calculation:

One because Potassium is in the first column on the periodic table. Any element in the first column on the periodic table has one valence electron in their outer shell.
Nickel contains more atoms.
<u>Explanation:</u>
Number of atoms is determined by the Avogadro number.
1 mole of substance contains 6.022 X 10²³ atoms.
Given:
Mass of Nickel, Ni = 3.89g
Molecular weight of Ni = 58.6934g
Number of moles of Ni = 3.89/58.6934g
Number of atoms of Ni = 
Number of atoms of Ni = 0.39 X 10²³
Mass of silver, Ag = 6.61g
Molecular weight of Ag = 107.8682g
Number of moles of Ag = 6.61/107.8682
Number of atoms of Ag = 
Number of atoms of Ag = 0.36 X 10²³
Therefore, Nickel contains for atoms.