The correct answer is A. Most reactive non metals.
Firstly if some one knows how to read the periodic table he would have no confusion in deciding whether group 7 has metals or non metals. Group 7 contains non metals so basically we can easily cancel out two options of metals.
Secondly group 7 non metals are the most reactive non metals as they need only one electron in order to complete their valence shell and become stable.
Answer:
Systems always tend toward a state of decreasing order unless more energy is provided into the system to counteract this tendency.
Answer:
Isolated or Closed system, both are correct
Speed can never be negative because it does not depend in which direction the car moves whereas, velocity will change if a car turns from due North to East.
Quantities which can be described only by their magnitudes are called scalars and those which are described by both, magnitude and direction are vectors
That would be a frequency of 1.2666... beats per second. This can be phrased as your heart beats at 1.27 Hz.
