What do the numbers listed for an element on the periodic table represent
2 answers:
There are usually two values you'll come across on the periodic table.
1. the atomic number.
this represents the number of protons an element has. For example, hydrogen (H) has an atomic number of 1, which means that hydrogen has only one proton.
2. the mass number.
this usually represents the number of protons and neutrons an element has. For example, carbon (C) has a mass number of roughly 12, which means that the sum of its protons and neutrons add up to about 12. We know carbon has an atomic number of 6 (6 protons) so the number of neutrons must be 6 aswell.
(the mass numbers can differ depending on which periodic table you are given)
1. the atomic number.
this represents the number of protons an element has. For example, hydrogen (H) has an atomic number of 1, which means that hydrogen has only one proton.
2. the mass number.
this usually represents the number of protons and neutrons an element has. For example, carbon (C) has a mass number of roughly 12, which means that the sum of its protons and neutrons add up to about 12. We know carbon has an atomic number of 6 (6 protons) so the number of neutrons must be 6 aswell.
(the mass numbers can differ depending on which periodic table you are given)
You might be interested in
Answer: Energy of reactants = 30, Energy of products = 10
Exothermic
Activation energy for forward reaction is 10.
Explanation:
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.
Energy of reactants = 30
Energy of products = 10
Thus as energy of the product < energy of the reactant, the reaction is exothermic.
Activation energy is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.
for forward reaction is (40-30) = 10.