Answer:
1,2,5
Explanation:
Hydrogen can't really be classified into any group in the periodic table because it doesn't have properties that match that of any group exactly. However it exhibits a property of group 1A (formation of a univalent positive ion) and that of group 7A (formation if a univalent negative ion). It contains only one electron, hence this outermost electron is not shielded at all from the nucleus.
Answer: The velocity of the first ball is 0.875 m/s if the second ball travels at 1.5 m/s after collision.
Explanation:
Given:
= 0.2 kg,
= 0.15 kg
= 2 m/s,
= 0 m/s,
= ?,
= 1.5 m/s
Formula used is as follows.

where,
v = velocity before collision
v' = velocity after collision
Substitute the values into above formula as follows.

Thus, we can conclude that the velocity of the first ball is 0.875 m/s if the second ball travels at 1.5 m/s after collision.
Answer:
Most similar - Lithium
Least similar - Phosphorus
Explanation:
Rubidium is an element in group 1A of the periodic table. It is a metal and forms an ionic compound with chlorine. The formula of the compound is RbCl.
If we look at the options, Lithium is also a group 1A element and forms an ionic compound with chlorine having the formula LiCl which is very much similar to RbCl chemically.
Phosphorus is a nonmetal. Its compounds with chlorine, PCl3 and PCl5 are covalent and does not resemble RbCl in any way.
Answer:
Anything that shares electrons.
Explanation: This means they don't transfer electrons.