Metals and non-metals can be told apart by their physical features. Let’s break it down.

Metals:

• Conductivity: Metals are great at carrying heat and electricity. For example, copper is really good at this.
• Luster: Metals shine and look shiny because they reflect light well.
• Ductility: Many metals can be stretched into thin wires. For example, gold can be stretched to make a wire that's about 50 kilometers long!
• Malleability: Metals can be hammered or rolled into thin sheets. Aluminum can be made super thin, around 0.5 millimeters.
• Density: Metals are usually pretty heavy for their size. For instance, lead is very dense.

Non-metals:

• Brittleness: Non-metals are usually brittle when they’re solid, which means they can break easily.
• Poor conductivity: They don’t conduct heat and electricity very well. For instance, sulfur is not a good conductor.
• Varied states: Non-metals can be different states of matter. They can be gases like oxygen, liquids like bromine, or solids like carbon.

These differences help us sort elements in the periodic table.