Answer:
Group 18th
Explanation:
The group 18th of periodic table which is composed of Noble gases mainly was missing from the Mendeleev's periodic table. The reason for this is that Noble gases are least reactive, therefore, it was difficult to predict such elements which do not react with other elements.
Object one is 5.2 g/cm3
object two is 3.46g/ml
Answer: increases by
As a chlorine atom becomes a negative ion, the atom "increases by" an electron
Explanation:
Chlorine atom has an atomic number of 17, and an electronic configuration of 1s2, 2s2 2p6, 3s2 3p5 showing 7 valence electrons in its outermost shell.
Hence, it receives a single electron to achieve a stable octet structure with electronic configuration of
1s2, 2s2 2p6, 3s2 3p6. Therefore, Cl- is a univalent negative ion with 8 valence electrons in its outermost shell. The increase is shown below
Cl + e- --> Cl-
Thus, as a chlorine atom becomes a negative ion, the atom "increases by" an electron
