Dimitri Mendeleev was the first to put elements together on a table. He knew there were elements missing but he noticed a trend in some of the elements known at the time. Sodium, Lithium and other alkali metals all have the same properties so he put them under the same column and created other columns with similar attributes (Halogens, Noble gases, Alkaline earth metals). Over the years, new elements were discovered and put into the rough outline that Mendeleev created.
I hope that is about what you wanted.
should be nonpolar covalent bond i believe, the electronegativity is the same
Answer:
Since different isotopes of an element have different numbers of neutrons (but always the same number of protons) they have different mass numbers. Nitrogen-14 and nitrogen-15 are both stable isotopes of nitrogen. However, the other 5 isotopes are all unstable.
Answer:
increases the frequency of particle collisions
Explanation:
One factor upon which the rate of reaction depends is the surface area of reactants.
According to the collision theory, reactions occur when reactant particles having the required (activation) energy collide with each other, this collision is inelastic. However, collision of particles having energies less than the activation energy results in elastic collisions and no chemical reaction.
The more the exposed surface area of reactants, the greater the number of particles that come into contact with each other and the more the chances of frequent effective collisions that lead to reaction.
Thus, powdered zinc reacts faster with hydrochloric acid than zinc strips
1. Potential of a chemical substances to undergo transformation in a chemical reaction is known as chemical energy. The chemical energy is stored in the bonds of chemical compounds.
Hence, in a compound, chemical energy is contained in bonds.
2. The process in which one or more substance known as reactants are converted to one or more completely new substances known as products are formed is known as a chemical reaction.
Hence, during a chemical reaction bonds of the reactants are broken, and bonds of the products are formed.