Knowledge MountainA PLACE FOR EVERY CURIOUS MINDORIGINAL STARTER TRAIL / Chemistry
Small particles. Big explanations.
FIELD NOTE / Chemistry
The atomic number is the number of protons. An atom with 6 protons is carbon; one with 8 is oxygen. Changing the electron count makes an ion of the same element, while changing the proton count changes which element it is.
A way to rememberProtons = the element’s passport.
Yes. Eight protons identify oxygen. With two more electrons than protons, its net charge is −2.
FIELD NOTE / Chemistry
Isotopes of an element have the same number of protons but different numbers of neutrons. Mass number counts protons plus neutrons. Carbon-12 has 6 protons and 6 neutrons; carbon-14 has 6 protons and 8 neutrons. Mass number is not the decimal atomic weight shown on a periodic table.
A way to rememberSame passport, different packed weight.
Carbon-13: 6 identifies carbon, and 6 + 7 = 13 gives the mass number.
FIELD NOTE / Chemistry
A proton has charge +1, an electron −1, and a neutron 0 in elementary charge units. Net charge = number of protons − number of electrons. Losing electrons creates a positive ion; gaining electrons creates a negative ion.
A way to rememberSubtract electrons: p − e.
+1: 3 − 2 = 1. It is a positive lithium ion because it has 3 protons.
THE PARTICLE BENCH
Change one kind of particle at a time. What stays the same?
A count model, not electron orbits. Not every selectable isotope or ion is stable in nature.
Mass number = 8 + 8 = 16
Charge = 8 − 8 = 0
A practice check, not an exam. Pick an answer for each question, then read the reasoning.
Lesson completion is self-reported. Checkpoint scores reflect these practice questions, not a qualification or certified mastery.