3 When the solid iron bar is heated, it no longer fits the holder .Use particle theory to explain why this happens

What rule is used to determine how many covalent bonds an element can form? a. the number of covalent bonds is equal to six c the number of covalent bonds is equal to five minus the group number plus the group number b. the number of covalent bonds is equal to eight d. none of the above minus the group number select the best answer from the choices provided

An atomic nucleus is composed ofa)protons. b)protons and neutrons. c)protons and electrons. d)protons, neutrons, and electrons.

Ok, so i have 2 questions. try to answer them both: (the topic is fire) 1) how can you represent the chemical reaction of fire? 2) what kind of bond is formed in this chemical reaction