Which of the following explains why a bicycle uses a lever?
reduces the effort force*i picked this one
increases the effort force
reduces the resistance force
increases the resistance force

These models show the electron structures of two different nonmetal elements. which element is likely more reactive, and why? element 1 is more reactive because it has fewer electron shells and is toward the top of its group on the periodic table. element 1 is more reactive because it has more electrons in its valence shell and is farther to the right on the periodic table. element 2 is more reactive because it does not have a valence shell close to the nucleus, so it will attract electrons. element 2 is more reactive because it does not have a full valence shell, so it will attract electrons.

If a substance is in the gas phase, which of qualities of the gas will stay constant? a: volume b: mass c: shape d: position of particles

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?