Introduction to Atoms Flashcards
What is an Atom?
The basic building blocks of matter
The smallest particles of an element that retain the chemical properties of that element
Combine to form molecules which make up al substances
What is the structure of an atom?
Three main subatomic particles
Proton, Neutrons, Electrons
Protons + Neutrons are found in the center = Nucleus
Electrons orbit the nucleus in energy levels/shells
Protons
Have a + charge and contribute to the mass of the atom
Neutrons
Have no charge and contribute to the mass of the atom
Electrons
Have a - charge and are much smaller in mass
What is the Atomic number?
The number of protons in an atom
What is the Atomic mass?
The sum of the protons and neutrons in the nucleus
What is an Isotope?
Atoms of the same element with different numbers of neutrons
What are Electron Shells?
Electrons occupy specific energy levels or shells around the nucleus
Inner most shell hold up to 2 electrons, second holds up to 8
Outermost shell is know as valence shell - determine the chemical behaviour of an atom
Valence electrons
Electrons in the outermost shell
The number influences how atoms interact with each other in chemical reactions
Elements in the same group of the periodic table have similar valence electron configurations
Definition of Elements
Substances made up of only one type of atom
Cannot be broken down into simpler substances by chemical means
Examples of Elements
Oxygen (O)
Hydrogen (H)
Carbon (C)
Properties of Elements
Each element has its own unique set of physical & chemical properties
Elements are organized in the periodic table based on their properties
Definition of compounds
Substance made up of two or more different types of atoms chemically bound together
Can be broke down into simpler substances by chemical means
Examples of Compounds
Water (H2O)
Carbon dioxide (CO2)
Sodium Chloride (NaCl)