What is the average mass of a single chlorine atom in grams?
Answers I tried and failed:
70
2.13x10^25
5.88x10^23
1.178x10^-22
2.13x10^-21

m = 5.81x10-²³ g Cl

Explanation: First is to find the number of moles of Cl in 1 atom of Chlorine. To solve this we will use the Avogadro's Number to convert atoms to moles.

1 atom Cl x 1 mole Cl / 6.022x10²³ atoms Cl

= 1.66x10-²⁴ moles Cl

The next step is to convert the moles of Cl to mass using its molar mass.

1.66x10-²⁴ moles Cl x 35 g Cl / 1 mole Cl

= 5.81x10-²³ g Cl.

Cancel out the units of moles Cl.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

no, the red giant is the hottest with 2.00.000.000 degrees celsius. while the white dwarf only 25,000 degrees celsius.