Question

1. During a chemical reaction old atoms disappear to be replaced by new ones. True or False

2. The difference between an element and a chemical compound is a chemical compound is always more massive than an element. True or False

3. Elements of a compound connotation be separated from one another by physical means because these elements found within a compound tend to be inert. True or False

4. The number of elements in a period is equal to the electron capacity of the shells. True or false

5. As atoms get more massive they become smaller in size because more mass means more protons, which act to pull electrons in closer to the nucleus. True or false.

Answer 1

1. False During a chemical reactions, atoms forms bonds or break bonds to form new products. The existing atoms won't be destroyed and no new atoms are formed

2. False The difference between element and a compound is, a compound is an entity that formed by grouping up of elements. That is compounds are group of elements. It is not necessary that, compounds will have more mass than an element.

For example Potassium which is an element is heavier than Hydrogen fluoride (HF) which is a compound

3. False Elements in a compound can be separated by breaking the bonds between them. The bond breaking can be done by physical means like heating, giving energy by irradiating radiation and giving electricity.

4. False Though it is true for 1st and 2nd periods, it is false for 3rd. The capacity of the 3rd shell is 18, but 3rd period only contains 8 atoms

5. False In a period, we can see the trend. As mass increases, nuclear charge (protons) increases and size of atoms decreases. But it is false, if there are more number of shells in an atom. As number of shells in an atom increases, obviously the mass increases, but each of the succeeding shell will be situated far from the nucleus and hence size of the atom increases. This can be evidently seen when moving down the group.