hydrogen - an element with only one proton it is lighter than air, carbon dioxide - a green house gas which is also a waste product of respiration, bubbles - if a reaction produces a gas you will see ?????? appear, hydrocarbon - a long chain molecule made of carbon and hydrogen only which when burned produces carbon dioxide and water, oxygen - a group 6 element which is part of the atmosphere we use for respiration, chlorine - a group 7 element which has 17 electrons and is. pale yellow gas, nitrogen - the element that makes up most of the atmosphere, sink - what happens to an element is more dense than air?,

Leaderboard

Visual style

Options

Switch template

Continue editing: ?