Looking across period 4 of the periodic table, potassium (atomic number 19) is followed by calcium (atomic number 20), which is followed by scandium (atomic number 21). which element should have the largest atomic radius? a) potassium b)calcium c)scandium d)all three have the same atomic radius.

For the following reaction, 5.65 grams of oxygen gas are mixed with excess hydrochloric acid . assume that the percent yield of water is 86.4 %. hydrochloric acid(aq) + oxygen(g) water(l) + chlorine(g) what is the ideal yield of water ? grams what is the actual yield of water ? grams

When the earth was formed and cooled, why did nickel and iron end up in the center of the earth while basalt and granite ended up in the outer layers

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)