Answer:
The cause of periodicity in properties is the repetition of similar outer electronic configuration after certain regular intervals. For example, all the elements of group 1 i.e. alkali metals have a similar outer electronic configuration, ns1.
Answer:
Dived the numbers by each other
Explanation:
25.3/19.9
Answer:
C
water changes temperature slowly i believe C is your anwser
R = 1.3 A° = 1.3 × 10^(-10) m


V = 9.20277208×10^(−30) m.