4.1Atoms and the Periodic Table
Atoms and the Periodic Table — Cambridge Checkpoint Science 0893 Revision Notes & Topical Questions
5 min read 6 parts Lesson 1 of 1 1 quiz
Lesson summary
4.1 Atoms and the Periodic Table — CHECKPOINT (CHEMISTRY) notes: Describe atoms, the structure of the atom, symbols and the layout of the Periodic Table.Atom = a tiny particle of matter; atom means cannot be dividedDemocritus suggested over 2000 years ago that matter is made of t…
- Seeing atoms
- Types of atom
- No overall charge
- Atomic number
- Mass number
- Metals and non-metals
Section 1 of 6Atoms
- Atom = a tiny particle of matter; atom means cannot be divided
- Democritus suggested over 2000 years ago that matter is made of tiny pieces.
- Seeing atoms
- large atoms can be seen with scanning tunnelling microscopes
- Types of atom
- 94 types occur naturally and 24 more have been made in laboratories, giving 118 known elements
Section 2 of 6Inside the atom
- Nucleus
- a tiny central part holding protons (positive) and neutrons (no charge)
- Electrons
- negative particles that move around the nucleus in shells
- No overall charge
- the number of protons equals the number of electrons
- Atomic number = the number of protons; it identifies the element
- Mass number = protons + neutrons
Section 3 of 6The Periodic Table
- Periodic Table = an arrangement of the elements, with similar elements close together
- Period = a row of the table; the mass of atoms increases across it from left to right
- Group = a column of the table
- Metals and non-metals
- metals are on the left and non-metals on the right
Section 4 of 6Groups and periods
- Groups
- elements in the same group react in similar ways because they have the same number of outer electrons
- Periods
- the period number tells how many shells the atoms have
- Noble gases
- group 0 gases are unreactive because the outer shell is full
- Mendeleev
- arranged the first Periodic Table and left gaps for undiscovered elements
Section 5 of 6Chemical symbols
- Symbol
- a shorthand way of referring to an element
- Capital letter
- the first letter is always upper case and the second, if any, is lower case
- Symbol sources
- the first letter of the name (O, oxygen), two letters of the name (He, helium) or another language
- (Na from natrium, Pb lead, Cu copper, Fe iron)
- the first letter of the name (O, oxygen), two letters of the name (He, helium) or another language
Section 6 of 6First twenty elements
| Element | Symbol | Element | Symbol |
|---|---|---|---|
| Hydrogen | H | Sodium | Na |
| Helium | He | Magnesium | Mg |
| Lithium | Li | Aluminium | Al |
| Beryllium | Be | Silicon | Si |
| Boron | B | Phosphorus | P |
| Carbon | C | Sulfur | S |
| Nitrogen | N | Chlorine | Cl |
| Oxygen | O | Argon | Ar |
| Fluorine | F | Potassium | K |
| Neon | Ne | Calcium | Ca |
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