Noble gases are the least reactive of all elements. That's because they have eight valence electrons, which fill their outer energy level. This is the most stable arrangement of electrons, so noble gases rarely react with other elements and form compounds.
Answer:
..............what.......
Answer:
Technetium, Promethium, Astatine, Francium
Explanation:
The rate of change of the temperature of the Earth's surface is given to,
90°F/mile
To determine the temperature x miles away from the surface, we multiply the depth by the given rate. This will give us the answer of,
T = (90°F/mile)(90 mile)
= 8100°F
Thus, the temperature 90 miles deep in the Earth's surface is equal to 8100°F.
Answer:
Ex1 = 4.3 moles
Explanation:
for Ex 1
** Number of mole = Mass (g) / Molecular weight ' Mw' (g/mole)
for a = NaCl , first you must be calculate Mw = look to periodic table
Atomic weight for Na is 22.9 = 23 g and for Cl is 35.45 = 35 g
so Mw for NaCl = 23+35 = 58 g/mole
so Number of Moles for NaCl 250 g is
Number of Moles = 250 / 58 = 4.3 moles
do same for others ...
good luck ..
