Which of the following statements about the periodic trend of atomic radius is/are true? i. atomic radius decreases from left to right across a period because zeff increases. ii. atomic radius increases from left to right across a period because the number of valence electrons increases. iii. atomic radius increases from top to bottom in a group because the number of electron shells increases. 1. i only 2. i and iii only 3. ii and iii only 4. ii only

Mass (kg) force (n) 5 25 10 50 15 75 20 100 a student was trying to find the relationship between mass and force. he placed four different masses on a table and pulled them using a spring scale. the table shows the different masses used in the experiment and the force required to pull each mass. the student concluded that more force was required to pull heavier objects. what comment would you make regarding his conclusion? a) no clear relation can be observed between mass and force from the data. b) there is a direct proportion between the mass and force listed in the table. c) gravity should have been taken into account while performing the experiment. d) there is an inverse proportion between the mass and force listed in the table.

4. if you were an astronaut on the moon, what would you experience? what would you see from your perspective?

Charge is distributed along the entire x-axis with uniform density λ. how much work does the electric field of this charge distribution do on an electron that moves along the y-axis from y = a to y = b? (use the following as necessary: a, b, ε0, λ, and q for the charge on an electron.)