You and everything around you are made up of matter. what is matter made up of? a. atoms and molecules b. atoms and helium c. gold and iron d. copper and potassium

An unknown substance is a white solid at room temperature and has a melting point of 78 °c. which of the following substances is most likely to be the identity of the unknown sample? a. naphthalene, a molecular solid with the formula c10h8 b. silica, a network solid held together by covalent bonds with the formula sio2 c. calcium chloride, an ionic compound with the formula cacl2 d. water, an molecular compound with the formula h2o

How many more valence electrons does sodium need to have a full outer valence shell

K12 chemistry unit assessment: chemical bonding, electrostatic forces in ionic bonds hold which of the following together? 1. he atoms in helium gas 2.na+ and br- in nabr 3. fe atoms and localized electrons in iron