Why nucleus of an atom is negatively charged?

An atom consists of a positively charged nucleus, surrounded by one or more negatively charged particles called electrons. The positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. ... The nucleus of an atom contains protons and neutrons

Explanation:

why is arctic sea ice important? arctic sea ice keeps the polar regions cool and moderate global climate. sea ice has a bright surface; 80 percent of the sunlight that strikes it is reflected back into space. as sea ice melts in the summer, it exposes the dark ocean surface.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).