Understanding Elements Quiz

Study Notes

The position of an element in the periodic table is determined by the number of protons it has.
A periodic table consists of rows (periods) and columns (groups).
Elements in the same period have the same number of energy levels, while the number of electrons in the outer shell increases as you move from left to right.
Elements in the same group have the same number of energy levels and the same number of electrons in their outer shell.
The periodic table traditionally includes four main groups: Group 1 (alkali metals), Group 2 (alkaline earth metals), transition metals, Group 17 (halogens), and Group 18 (noble gases).
Atoms form molecules by either sharing or transferring electrons to enhance stability.
Molecules can be homonuclear (made up of the same element, like an oxygen molecule) or heteronuclear (made up of different elements, like water).
Molecules can be categorized by the number of atoms they contain: monatomic (one atom, like helium), diatomic (two atoms, like oxygen gas), triatomic (three atoms, like water), tetratomic (four atoms, like phosphorus), pentatomic (five atoms), and hexatomic (six atoms).
Compounds are pure substances formed when at least two different elements combine chemically and have their atoms bonded together.
Compounds have a fixed number of atoms and are represented by a fixed formula.
Elements in a compound are not easily separated by physical and chemical means but can be chemically broken down.
Examples of compounds include potassium carbonate (K2CO3), magnesium nitrate (Mg(NO3)2), copper sulfate (CuSO4), sodium chloride (NaCl), copper sulfide (CuS), and water (H2O).
All compounds are molecules, but not all molecules are compounds.