Chlorine and element X have similar chemical properties. An atom of element X could have an electron configuration of -- Group of answer choices

1s2 2s2

1s2 2s2 2p6 3s2 3d10 3p6 4s2 4p5

1s2 2s2 2p6 3s1

1s2 2s2 2p6 3s2

A50.0g sample of liquid water at 0.0 c ends up as ice at -20.0 c. how much energy is involved in this change?

Calculate the estimated density of each ball. use the formula d = m/v where d is the density, m is the mass, and v is the volume. record your calculations in table a of your student guide. given that the density of water is 1.0 g/cm3, make a prediction about whether each ball will float in water. record your prediction in table a. what is the estimated density of the table tennis ball? record your answer to the nearest hundredth

As we move from left to right across the periodic table, what is the general trend? a) atomic radii increase. b) electronegavitiy decreases. c) nuclear shielding increases. d) metallic character decreases.