Question

answer any 2 please..​

Answer 1

Answer:

1.Mendeleves Periodic law:- properties of the element is the periodic function of their atomic mass.

2.Principle of heat exange is used to measure heat capacity of a substance.

4. see the photo. For methane draw dots instead of lines and for ethene it's given.

Answer 2

Mendeleev periodic law

Explanation:

the properties of the elements are the periodic functions of their atomic masses.

1. Mendeleev arrange the elements in increasing order of their masses and the element lying in the group have same properties.

2. 63 elements were known at that time.

3. he made a table of 8 groups (vertical columns) and 6 periods (horizontal rows).

modern periodic law.

1. properties of the elements are periodic function of their atomic number.

2. atomic number equals to number of protons.

number of proton equals to number of electron.

number of neutrons can vary but number of protons remain the same in an atom.

3. it has 7 periods and 18 groups.

periodic number of an element equals to number of shells

distribution of electrons in a cell is determined by the formula 2n^ where n is the cell number.

first period is the shortest.

sixth period is the longest.

seventh period is incomplete.