What are the elements whose discovery added an entirely new column to mendeleev's periodic table?

What is the number of atoms in 3.54 mol s

Is 343 in the sequence -5, -2, 1, 4, 7

Polar bears give birth and hunt on sea ice. which of the following would polar bears survive during the melting of arctic ice? growing another layer of fur during summer migrate inland to search for different food sources staying put until the ice refreezes sticking to the usual diet of seals