When an atom loses an electron, it loses a negative charge and becomes this.
What is a positive ion?
100
This is the number of protons in the nucleus of an atom.
What is an atomic number?
100
A change in matter that produces a new substance.
What is a chemical change?
100
He described that an atom has negatively charged particles scattered through a ball of positive charge.
Who is Thomson?
200
The study of matter.
What is chemistry?
200
When an atom gains an electron, it gains a negative charge and becomes this.
What is a negative ion?
200
As the number of protons (atomic number) increases, the number of these also increases. As a result, the properties of the elements change in a regular way across a period.
What are electrons?
200
The number of this in an atom of an element determines many properties of that element, including the ways in which the atom can bond with other atoms.
What is a valence electron?
200
He inferred that an atom's nucleus contains the positive charge.
Who is Rutherford?
300
The center of an atom.
What is a nucleus?
300
For an ionic compound, the name of the ___________ ion comes first.
What is the positive ion?
300
These are the major groups in the periodic table.
What are halogens, noble gasses, various metal and non-metal groups?
300
An atom or group of atoms that have an electric charge.
What is an ion?
300
He showed that electrons could have only specific amounts of energy, leading them to move in certain orbits.
Who is Bohr?
400
A pure substance made of one type of atom.
What is an element?
400
These are hard, brittle crystals that have high melting points. When dissolved in water or melted, they conduct electricity.
What are ionic compounds?
400
A period end whens the highest energy level has eight of these.
What are electrons?
400
The chemical bond formed when two atoms share electrons is called this.
What is a covalent bond?
400
Thought that atoms were like smooth hard balls that could not be broken down.
Who is Dalton?
500
The amount of matter in an object.
What is mass?
500
Ions that are made of more than one atom.
What are polyatomic ions?
500
The atoms in these periods want to give away electrons, to become more stable.
What is period one and two?
500
This includes the symbol for the element surrounded by dots.
What is an electron dot diagram?
500
In 1932, this new particle was hard to detect because it has no electrical charge even though it has nearly the same mass as a proton