Which one of the following substances is a compound? A. Hydrogen B. Iron C. Oxygen D. Sodium fluoride

The alkali metals (group 1) consist of lithium (3), sodium (11), potassium (19), rubidium (37), cesium (55), and francium (87). they are soft, metallic solids with low densities and low melting points. based on the data shown in figure 1, how many valence electrons do alkali metals share?

Choose all the answers that apply. as ocean depth increases, temperature decreases temperature increases pressure increases pressure decreases salinity increases density increases

How does kepler second law of planetary motion overthrow one of the basic beliefs of classical astronomy