Define:
element
Atoms are the individual units of each element. For example, hydrogen (H) and oxygen (O) are elements, while water (H2O) is not.
Explain:
What characteristic identifies an atom as a specific element?
The number of protons, known as the atomic number.
Example: Carbon has an atomic number of 6.
Identify:
3 main subatomic particles that make up an atom.
These particles define the structure and properties of an atom.
Protons and neutrons are found in the nucleus, while electrons are in the electron cloud.
Define:
proton
Positively charged subatomic particle with a mass of approximately 1 amu.
Protons are found in the nucleus of an atom.
Define:
atom
The smallest unit of matter that retains the properties of an element.
Atoms are composed of subatomic particles and cannot be broken down into other substances.
Define:
atomic mass unit
(amu)
Standard unit of mass used for measuring particles as small as subatomic particles.
Define:
atomic number
It is the number of protons in an atom. It defines the atom as a specific element.
Describe:
What happens when an atom gains or loses electrons?
It becomes an ion; losing electrons creates a cation and gaining electrons creates an anion.
Ions carry a charge due to the imbalance of protons and electrons.
Define:
neutrons
Neutral subatomic particles located in the nucleus with protons.
They have a mass of about 1 amu.
Describe:
How is the atomic mass of an atom calculated?
It is equal to the number of protons plus the number of neutrons.
Electrons contribute negligibly to the atomic mass.
Define:
isotopes
Atoms with a different number of neutrons than the average number for that element.
Isotopes can be stable or unstable, with the latter undergoing radioactive decay.
Define:
periodic table
A chart organizing all elements by their physical and chemical properties based on atomic number.
Each element is represented by its atomic number, chemical symbol, abbreviation and atomic mass.
Explain:
How are atoms created?
Through nuclear fission or nuclear fusion.
Fission splits larger atoms, while fusion combines smaller atoms.
Describe:
The nucleus of an atom.
The dense center of an atom containing protons and neutrons.
Most of the mass of an element is found in the nucleus.
Explain:
The difference between metals and non-metals.
Most elements are metals.
Define:
halogens
Highly reactive non-metals found in Group 7 of the Periodic Table.
They include fluorine, chlorine, bromine, iodine, and astatine.
Identify:
What defines the properties of an element?
The number of subatomic particles it contains.
Protons, neutrons and electrons determine unique characteristics.
Describe:
molecule
It is composed of at least two atoms joined by a chemical bond.
Atoms of elements build different molecules.
Define:
compound
A group of molecules.
For example, water is a compound, a group of individual H2O molecules.
Explain:
How do elemental personalities affect their bonding?
Elements with stable outer electron configurations tend to remain unbonded, while those with unstable outer shells tend to form bonds to achieve stability.
List:
The two types of chemical bonds.
Identify:
The difference between a pure substance and a mixture.
Explain:
How can you determine if a bond is ionic?
If it conducts electricity when dissolved in pure water.
Explain:
What happens to the components in a mixture?
They keep their own chemical identities.