Question | Answer |
Who discovered small negatively charged particles called electrons? | J.J. Thomson |
Opposite charges do what with each other? | Attract |
Like charges do what with each other? | Repel |
What is the center of an atom which contains most of the atom's mass? | Nucleus |
What are the positively charged particles inside an atom's nucleus called? | Protons |
The particle that is found in the nucleus of an atom and has no electrical charge is a what? | Neutron |
In Ernest Rutherford's "gold foil experiment", he discovered that what is mostly empty space? | An atom |
Each energy level can hold a certain number of electrons. The first energy level is closest to what and can hold how many electrons? | Nucleus and 2 |
When the first energy level is full, electrons begin to fill the second level. The second energy level can hold how many electrons? | 8 |
When the second energy level is filled, electrons go to the next higher level. The last occupied energy level might or might not be filled. | True |
The electrons in the outermost level are called what? | Valence electron |
These outermost electrons are in involved in what? | Chemical bonding |
If the atoms of a substance have their outer energy levels filled, they are what? Which means, if the outer energy level is filled, the atom will not combine with another atom to form a new substance. | Unreactive |
Atoms with partially filled outer energy levels likely or unlikely to bond with other atoms? | Likely |
Electrons are located within an area around the nucleus called what? | Electron cloud |
What two parts of the atom has the same mass? | Protons and Neutrons |
What has a small mass? | Electron |
The most mass of an atom is found in the what? | Nucleus |
Pure substances that cannot be broken down into any simpler substance is a what? | Element |
Each element has atoms consisting of a specific number of what? | Protons, neutrons, and electrons |
The number of protons in an atom of an element is its what? | Atomic number |
Atoms normally have the same or different numbers of electrons as protons? | The same |
Atoms of the same element that have different numbers of neutrons are called what? | Isotopes |
The sum of the number of protons and neutrons in the nucleus of an atom is the atoms what? | Mass number |