MULTIPLE CHOICE QUESTION What is the density of an irregularly
shaped object with a mass of 7.8 g and
which, when added to a measuring
cylinder with water, raised the level of
water from 10.45 mL to 23.38 mL?

Can someone me with these questions plz.

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?

What layer of the atmosphere is directly above the troposphere?