Is carbon a metal or a nonmetal? How many valence electrons does a carbon atom have?

Which object forms when a supergiant runs out of fuel? a red giant a black hole a white dwarf a neutron star

This is a characteristic of the elements in the periodic table that shows a pattern. it may increase or decrease across or down the table.

Zoe is investigating the composition of substance a, an unknown substance. using chemical processes, she analyzes substance a and determines it is composed of sodium, oxygen, and hydrogen atoms in a ratio of 1 : 1 : 1. what is substance a? a. a compound b. an element c. a heterogeneous mixture d. a homogeneous mixture