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chemistry

1. the periodic table is based on an element's
a. molecular size.
b. molecular mass.
c. atomic mass.
d. atomic number.

2. one atom of silicon can properly be combined in a compound with
a. two atoms of oxygen.
b. one atom of chlorine.
c. three atoms of hydrogen.
d. four atoms of calcium.

Match term definition ellipse a) diagonal cross section of a cylinder circle b) diagonal cross section through the widest part of a sphere sphere c) cross section parallel to the base of a cone great circle d) shape created when a semi-circle is rotated around the y-axis triangle e) perpendicular cross section of a cone

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains

Which organism develops breathing organism develops breathing organs from pharyngeal arches? shark, spider, sea star, sea horse