Raven lays a printed table across the Bench. "Every element has a state at room temperature," she says. "And a temperature where it melts."
Rocket scans the list. "Gold melts at over a thousand degrees. Oxygen melts at minus 219. Minus!"
"What do you notice about the elements that are gases?" Raven asks.
Rocket runs a finger down the column. "Their melting points are way below zero. They melted long before room temperature."
Nova hovers over the table and brightens one row. "Here is a metal that is a liquid right now, in this kitchen," she says. "Find it."
"Mercury!" Rocket says. "Melting point minus 39. It is already melted."
Raven nods. "A table like this lets you predict a state without touching anything."
Scientists keep tables of the properties of each element. The National Institutes of Health PubChem periodic table lists each element's state under standard conditions.
LibreTexts chemistry, a university hosted textbook, lists melting points in degrees Celsius for common materials.
The melting point is the temperature at which a solid changes into a liquid. Below it, the substance is a solid. Above it, a liquid, until it boils.
Here are both sets of data side by side. Room temperature lies far above the melting points of the gases and far below those of the metals.
| Substance | State at room conditions | Melting point (degrees Celsius) |
|---|---|---|
| Hydrogen | Gas | -259 |
| Oxygen | Gas | -219 |
| Nitrogen | Gas | -210 |
| Mercury | Liquid | -39 |
| Water | Liquid | 0 |
| Silver | Solid | 961 |
| Gold | Solid | 1063 |
| Iron | Solid | 1538 |
| Tungsten | Solid | 3422 |
Mercury is the only metal that is a liquid at room temperature. Every other metal is a solid at room temperature.
Tungsten has the highest melting point of any metal, 3422 degrees Celsius. Mercury has one of the lowest, minus 39.
About 80 percent of the elements are metals. Most metals are solids, which is why the kitchen is full of solid metal tools.
Some substances are gases at room temperature, such as oxygen and carbon dioxide. Others, like water and mercury, are liquids.
Mercury was used in thermometers for decades, until its toxicity became known. You will never handle it at the Bench.
| Statement | True or false? |
|---|---|
| Below its melting point, a substance is a solid. | ? |
| All metals are solids at room temperature. | ? |
| Hydrogen and oxygen have melting points far below zero. | ? |
| Iron melts at a lower temperature than silver. | ? |
| Water is a liquid at room temperature. | ? |
Great data reading. Tomorrow you will find the three states at work in everyday life and review the week.