The correct answer is A. Ammonia.
1) ₁₄Si 1s²2s²2p⁶3s²3p².
Principal quantum number (n=3) have four electrons (3s²3p²).
2) ₁₉K 1s²2s²2p⁶3s²3p⁶4s¹.
Azimuthal quantum number (l=o) have seven electrons (1s²2s²3s²4s¹).
3) ₈₀Hg [Xe] 4f¹⁴5d¹⁰6s².
Principal quantum number (n=4) have thirty-two electrons (4s²4p⁶4d¹⁰4f¹⁴).
The principal quantum number<span> is one of four </span>quantum numbers<span> which are assigned to each electron in an </span>atom<span> to describe that electron's state.</span>
The azimuthal quantum number<span> is a </span>quantum number<span> for an </span>atomic orbital<span> that determines its </span>orbital angular momentum<span> and describes the shape of the orbital. </span>
Velocity = 15 m/s
90/2 = 45 m
45/3 (seconds to reach) = 15 m