Electrons needed to make filled orbitals: 2 | 8 | 8 | 12 …
Carbon atom: PPPPPPNNNNNN | ee | eeee (four short of filling 2nd orbital)
Oxygen atom: PPPPPPPPNNNNNNNN | ee | eeeeee (two short)
What’s this? PPPPPPPPPPNNNNNNNNNN | ee | eeeeeeee ([Homework!] Name the element.)
1) [Homework!] Why is this element very stable and non-reactive – not subject to stealing or sharing or ionizing?
Hydrogen atom: P | e (one short)
IF SHORT, electrons can be stolen or shared to fill the orbit.
2) Homework: NITROGEN ATOMS: these have 7 protons. Thus what form of hydrogenated nitrogen should exist? How many electrons are shared when combining two N atoms to make nitrogen gas?
========= other observations ===========
Atomic Number is the number of protons in the atom’s nucleus.
Atomic Weight is the sum of the protons and neutrons in the atom’s nucleus.
(The atomic weight is usually not a whole number, because some atoms have more or less neutrons. Thus the atomic weight is an average.)
Isotopes are all the different atomic weights for atoms of the same atomic number. Thus hydrogen has three known isotopes: protium, deuterium and tritium. (About 0.1% of all natural hydrogen is deuterium (heavy hydrogen). Thus the atomic weight of hydrogen is slightly higher than 1.000 (weighted average: 0.999 x 1 + 0.001 x 2 = 1.001. (We don’t include tritium, because it is radioactive with a short half-life (12y) and thus is not naturally found.)
Some isotopes are unstable (radioactive).
, 3) (Homework!) Draw the anatomy of [radioactive] carbon-14. (One of the C-14’s neutrons disintegrates to form a proton and an escaping electron. The result is a non-radioactive N-14 atom. (Homework!)
4) If the half-life of C-14 is 12,500 years, how old is a bone in which there is only 1/4 as much C-14 as in a bone made yesterday?
Our earth atmosphere top four major constituents:
5) [Homework!] what are they and in what percentages? (FYI: methane is not one of them, although it is at about 0.0001% enough to lower the efficiency of photosynthesis by 10%.)