A molecule is the smallest part of A an element
B a compound
C a substance
D an atom

Check the correct box to describe the periodic trends in electronegativity. electronegativity across a period: decreases. increases. electronegativity down a group: decreases. increases.

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.

1. explain hydrogen peroxide, h 2 o 2 properties and decomposition reaction. 2. describe how each of the following natural cycles plays a part in earth’s climate system. (a) the water cycle (b) the carbon cycle