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.
The interaction between the atoms is due to number of electrons in the valence shell
The appropriate response is Proximity. Purposes behind going out on a limb of living unlawfully in another nation are not just the normal upgrades in pay and living conditions yet, in addition, the expectation of in the long run being permitted to stay in the nation legitimately, as there might be a way to getting to be plainly naturalized. Living in another nation wrongfully incorporates an assortment of confinements, and additionally the danger of being kept and expelled or of confronting different authorizations
B. the same number of protons.
Objects with more mass have more gravity. Gravity also gets weaker with distance. So, the closer objects are to each other, the stronger their gravitational pull is. Earth's gravity comes from all its mass.