ASVAB CampMatter, Atoms and the Periodic Table flashcards
8 cards with the formulas, rules and traps from this lesson. Answer in your head, then flip to check.
Term · 1/8
Name the six phase changes and the direction of each.
Melting: solid to liquid. Freezing: liquid to solid. Vaporization: liquid to gas. Condensation: gas to liquid. Sublimation: solid to gas. Deposition: gas to solid (frost).
Rule · 2/8
How do you decide whether a change is physical or chemical?
Ask whether a new substance forms. Changes of state, cutting and dissolving keep the same substance (physical). Rusting, burning and cooking make new substances (chemical).
Term · 3/8
Element, compound or mixture: what defines each?
Element: one kind of atom. Compound: two or more elements chemically bonded in a fixed ratio. Mixture: substances combined physically, not bonded, in any ratio and separable by physical methods.
Formula · 4/8
What is the density formula and its usual units?
: density equals mass divided by volume, in g/cm³ or g/mL (1 mL = 1 cm³). Objects less dense than a fluid (water is about 1.0 g/mL) float in it.
Formula · 5/8
How do you find protons, neutrons and electrons from atomic number, mass number and charge?
Protons = atomic number Z. Neutrons = mass number A minus Z. Electrons = protons minus charge. Example: (Z = 13) has 10 electrons.
Common trap · 6/8
Isotope versus ion: which particle count changes?
Isotopes of an element differ in neutrons, changing mass but not charge. Ions differ in electrons, changing charge. The proton count stays the same in both.
Common trap · 7/8
Why can't you get neutrons by subtracting Z from the decimal atomic mass on the table?
The decimal is a weighted average of the element's natural isotopes, not one atom's mass number. Use the isotope's mass number: copper-65 has 65 - 29 = 36 neutrons.
Fact · 8/8
What ion charges do groups 1, 2, 17 and 18 typically show?
Group 1 alkali metals: +1. Group 2 alkaline earth metals: +2. Group 17 halogens: -1. Group 18 noble gases: full outer shells, so they rarely form ions or react.