That the physical and chemical properties of the elements are periodic within the sequence of their atomic numbers. the law of conservation of mass newton’s 1st law thermodynamic law the periodic law

Option (d) is the correct answer.

Explanation:

According to the periodic law, physical and chemical properties of elements occur periodically when elements are placed according to the sequence of their atomic numbers.

For example, elements of a group show similar chemical properties as they have same number of valence electrons.

Elements of a period 3 show different characteristics and these characteristics are periodically repeated by elements of period 4.

Therefore, we can conclude that the Periodic law states that the physical and chemical properties of the elements are periodic within the sequence of their atomic numbers.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

the answer is definitely c.