On June 21, as seen from the North pole ...
-- the sun has been up, and it's been light outside,
for the past three months ... ever since March 21 .
-- The sun won't set, and it won't be dark outside,
for another three months ... until September 21.
-- Here at the North pole, it stays daylight for six months straight.
Today, on June 21, we're exactly halfway through the period of
continuous daylight.
Answer:
The mass number is defined as the total number of protons and neutrons in an atom.
Explanation:
Answer: 15.3 grams C
Explanation: 1 mole is 6.02x10^23 atoms. We can find the moles of C in 7.675 x 10^23 atoms of C by dividing:
(7.675 x 10^23 atoms C)/(6.02x10^23 atoms C/mole) = 1.275 moles C
The molar mass of carbon is 12g/mole. So the mass of 7.675 x 10^23 atoms is (1.275 moles C)*(12 g/mole C) = 15.3 grams.
Answer:
The first energy level is closest to the nucleus. The second energy level is a little farther away than the first. ... The electrons in the energy level farthest from the nucleus are called valence electrons. Atoms in the same column (group) in the periodic table have the same number of valence electrons.
Explanation:
