Answer:
Kr
Explanation:
the element that is in group 18 is noble gasses. the elements are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og).
Given:-
- Time taken by the particle (t) = 6 s
- Average speed (v) = 40 m/s
To Find: Distance (s) travelled by the particle.
We know,
s = vt
where,
- s = Distance travelled,
- v = Speed &
- t = Time taken.
Putting the values,
s = (40 m/s)(6 s)
→ s = 240 m ...(Ans.)
Benjamin Banneker did this in 1792. Hope this helps