Neils bohar proposed his atomic model in 1913.
He describe that's electron travel in a circular orbit surrounds the neuclus of an atom.each orbit has quantized energy and size. Energy is transmitted when an electron jumps from one to other orbit near to nucleus.and it absorb energy when it jumbs away from nucleus.he also said that these electrons are restricted to fixed orbits. In excited state of electron, they absorb or emitt photon with specific wavelength.
<span>The alkali metals and hydrogen are reactive because they have only one electron to give in order to complete their valence shell. It is easier to give that one electron so when given the opportunity they will. This means they will react with anything polar or willing to take an electron.</span>
Answer:
must be either a gas or liquid
Answer: The reaction is exothermic
The 
value is negative.
Heat is a product.
Explanation:
Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and for the reaction comes out to be positive.
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and for the reaction comes out to be negative.
The substances which are written on the left side of the arrow are reactants and the substances which are written on the right side of the arrow are products. Thus heat is a product.
<span>c] The golfer sent the golf ball flying toward the cup to score a hole in one.</span>
