What is the biome with a lot of trees

Which element forms an ionic bond with flourine? 1) fluorine 2) carbon 3) potassium 4) oxygen

You are making a solution of calcium chloride dissolved in water. you add solid, stir, and it dissolves. you add just a spatula tip full, stir, and the solid does not dissolve. how could you describe the solutions before and after adding the spatula tip amount

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?