Atoms 101
The smallest part of an element that still behaves like that element.
What is an atom?
A positively charged particle found in the nucleus.
What is a proton?
Atoms of the same element with different numbers of neutrons.
What are isotopes?
Electrons are arranged around the nucleus in these regions.
What are energy levels?
A chart that organizes all known elements by repeating properties.
What is the periodic table?
The center of an atom that contains protons and neutrons.
What is the nucleus?
A particle with no charge, found in the nucleus.
What is a neutron?
Group 2 elements have ____ valence electron(s).
What is two?
When electrons are in their lowest energy state.
What is the ground state?
A vertical column on the periodic table.
What is a group (or family)?
The number of protons in an atom determines this.
What is the atomic number?
These subatomic particles balance the charge of protons in a neutral atom.
What are electrons?
The average mass of all isotopes of an element.
What is the atomic mass?
When electrons absorb energy and jump to a higher level.
What is the excited state?
A horizontal row on the periodic table.
What is a period?
The modern atomic model describes electrons in regions called these, not fixed paths.
What are orbitals?
The approximate mass of a proton or neutron.
What is 1 amu (atomic mass unit)?
Oxygen has a mass number of 16 and atomic number 8. How many neutrons does it have?
What is 8?
The maximum number of electrons that can fit in the second energy level of an atom.
What is 8?
Across a period from left to right, elements become less ______.
What is reactive?
The total number of protons and neutrons in the nucleus.
What is the mass number?
The model that shows where electrons are most likely to be found around the nucleus.
What is the electron cloud model?
Group 8A elements with full valence shells and very low reactivity.
What are the noble gases?
Energy released when electrons fall back to ground state often appears as this.
What is light (photons)?
The scientist who first arranged elements into the periodic table.
Who is Dmitri Mendeleev?