Basics
The smallest unit of matter that retains the properties of an element.
Atom
What element has the atomic number 8?
Oxygen
The reactants in 2H₂ + O₂ → 2H₂O.
Hydrogen and Oxygen
This state of matter has a definite shape and volume.
Solid
The SI unit for temperature.
Kelvin (K)
This is the symbol for sodium on the periodic table.
Na
The elements in Group 18 are known as these gases.
Noble Gases
In a chemical reaction, mass is always ________.
Conserved
In this state of matter, particles are free to move but still close together.
The freezing point of water in Celsius.
0°C
This is the number of protons in a carbon atom.
6
Chlorine belongs to this group of nonmetals.
Halogens
When hydrogen and oxygen combine to form water, this type of reaction occurs.
Synthesis
When a liquid is heated to the point where its vapor pressure equals the external pressure, this process occurs.
Boiling
The density formula is mass divided by ________.
Volume
The particle in an atom that has no charge.
Neutron
The horizontal trends in atomic size decrease from this side to this side of the table.
Left to right
The number of oxygen atoms in 2CO₂.
4
The process of a liquid changing to a gas at the surface below boiling point.
Evaporation
Round 0.003468 to 2 significant figures.
0.0035
What is the molecular geometry of H2O?
bent or V-shaped
Elements with similar properties are arranged in these vertical columns.
Groups or families
This type of reaction involves a compound breaking down into simpler substances.
Decomposition Reaction
The temperature at which a solid turns into a liquid.
Melting Point
The number of significant figures in 0.00450.
3