1) How many valence electrons are in the alkaline earth metal family? Do they form cations or anions?
A)
1 valence electron, cations
B)
1 valence electron, anions
C)
2 valence electrons, cations
D)
2 valence electrons, anions

Air is held within a frictionless piston-cylinder container, which is oriented vertically. the mass of the piston is 0.45 kg and the cross-sectional area is 0.0030 m2. initially (state 1) the pressure of the gas is sufficient to support the weight of the piston as well as the force exerted by the atmospheric pressure ( 101.32 kpa). the volume occupied by the air within the cylinder in state 1 is 1.00 liter. one end of a spring (with spring constant k = 1000 n/m) is attached to the top of the piston, while the other end of the spring is attached to a stage that can move vertically. initially the spring is undeflected and therefore exerts no force. then the stage is then moved quasistatically downward a distance of 10.0 cm, at which point the system reaches state 2. the piston-cylinder is not insulated; rather it remains in diathermal contact with the surroundings, which are at a constant temperature of 300 k. what is the change of pressure within the container?

Two polarizers are oriented at 40∘ to each other and plane-polarized light is incident on them. if only 16 percent of the light gets through both of them, what was the initial polarization direction of the incident light?

Which planet do you think would be easiest for humans to colonize some day?