Flashcards · 9202 · Topic 1

Atomic structure and the periodic table flashcards

19 cards on Topic 1, subtopics 3.1.1 to 3.1.3. Pick a subtopic or study them all.

Study mode needs JavaScript. Every card is listed below, so you can still cover the answers and test yourself.

All 19 cards

For a quick read-through or printing. Cover the right-hand side to test yourself.

Particles in a solid, a liquid and a gas: Solid: close together in a fixed, regular arrangement; vibrate. Liquid: close together, irregular; move past each other. Gas: far apart, random; move quickly in all directions.
What happens to the particles when a solid melts?: They gain enough energy to overcome some of the forces holding them in a fixed arrangement, and start to move past each other while staying close together.
What happens to the particles when a liquid boils or evaporates?: They gain enough energy to overcome the remaining forces between them and spread apart to fill the container.
Name the changes of state: solid → liquid, liquid → gas, gas → liquid, liquid → solid: Melting; boiling (or evaporating); condensing; freezing.
What do diffusion experiments (bromine in air, NH₃ and HCl, KMnO₄ in water) show?: That particles are in constant, random motion.
Ammonia and hydrogen chloride gases diffuse towards each other in a tube. What do you see?: A white ring of ammonium chloride where the two gases meet.

Element: A substance made of only one type of atom, represented by a chemical symbol.
Relative charge and relative mass of a proton, a neutron and an electron: Proton: +1, mass 1. Neutron: 0, mass 1. Electron: −1, very small mass.
Atomic number and mass number: Atomic number: the number of protons. Mass number: protons + neutrons.
Protons, electrons and neutrons in ²⁷₁₃Al: 13 protons, 13 electrons, 27 − 13 = 14 neutrons.
Isotopes: Atoms of the same element (same atomic number) with different numbers of neutrons, so different mass numbers.
Electron structure of sodium (atomic number 11): 2,8,1 — shells fill 2, then 8, then the remainder.
Relative atomic mass, Ar: An average mass of the atoms of an element, compared with carbon-12.
How did the model of the atom change from the plum pudding model?: Alpha-particle scattering showed the mass and positive charge are concentrated in a tiny nucleus, so the nuclear model replaced the plum pudding model. Electrons were then placed in shells, and the neutron was found later.

How are the elements arranged in the modern periodic table?: In order of atomic (proton) number, with elements with similar properties in the same columns (groups).
For Groups 1–7, what does the group number tell you?: The number of electrons in the outer shell.
How did Mendeleev’s table allow undiscovered elements to be predicted?: He grouped elements by similar properties and left gaps where no known element fitted, then predicted the properties of the missing elements from their groups.
Why are the noble gases (Group 0) unreactive?: They have a stable outer shell: 8 outer electrons (helium has 2), so they have no tendency to gain, lose or share electrons.
Why do Group 1 and Group 7 elements react?: To reach a stable, noble-gas-like outer shell: Group 1 atoms lose their one outer electron; Group 7 atoms gain one electron.