Plz helppp me in this science question

1. Speed is a scalar quantity that refers to "how fast an object is moving." Speed can be thought of as the rate at which an object covers distance. A fast-moving object has a high speed and covers a relatively large distance in a short amount of time.

2. a. The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time.

   b. Acceleration is the rate of change of velocity.

3. It can be caused by friction.

Explanation:

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.