Chemistry - An Introduction Flashcards
What is the smallest unit of matter?
Atoms are the smallest unit of matter.
What is an element?
An element is a pure substance that contains only one type of atom.
What is a pure substance?
A pure substance is a substance that cannot be broken down into simpler forms. It is only composed one type of particle, including molecules, compounds or atoms.
Who proposed the concept of an atom?
A Greek philosopher named Democritus, proposed the concept of an atom.
How long ago was the concept of an atom first proposed?
The concept of an atom was proposed over 2500 years ago.
In what shape is an atom modelled as?
An atom is modelled in the shape of a sphere.
What are the smaller particles that make up an atom?
The smaller particles which make an atom are called subatomic particles.
How many subatomic particles are there in an atom?
There are three subatomic particles.
What subatomic particle has a positive charge?
The protons have a positive charge.
What subatomic particle has a neutral charge?
The neutrons have a neutral charge.
What subatomic particle has a negative charge?
The electrons have a negative charge.
Name the three subatomic particles.
Protons (+), neutrons (=) and electrons (–)
What is the structure of an atom?
The atom contains a nucleus found in the centre of the atom and shells in which the electrons “orbit” around.
What is the nucleus and what does it contain?
The nucleus is found at the centre of an atom. It contains the protons (positive charge) and the neutrons (neutral charge). These subatomic particles found in the nucleus can also be called nucleons .
What are the nucleons?
The nucleons refers to the internal content that is found in the nucleus, which contain the protons and neutrons.
What is the proton?
The proton is one of three subatomic particles found in an atom. It holds a positive charge and has nearly the equivalent mass of the neutron. It is also found in the nucleus of the atom.
What is the neutron?
The neutron is one of three subatomic particles found in the atom. It holds no charge (neutral) and nearly has the equivalent mass of the proton. It is also found in the nucleus of the atom.
What is the electron?
The electron is the smallest of the three subatomic particles. They hold a negative charge, and are responsible for orbiting around the nucleus from a far distance.
What overall charge do atoms have?
Atoms have an overall neutral charge.
Why do atoms have a neutral charge overall?
Atoms always have the same number of protons and electrons, which balance out the charge. As a result, this causes for no charge that is held by the atom.
What is a shell of an atom?
The shell is the space in which the electrons orbit around the nucleus from a far distance.
What part of the atom has the strongest influence on the properties and mass of an atom?
The nucleus contains the protons and neutrons, which are the heaviest subatomic particles in the atom. As a result, their great mass is responsible for majority of the atoms properties, features and mass.
How are there different types of atoms?
Different atoms are formed by different combinations of the number of protons, electrons and neutrons. Each subatomic particle, especially the proton and neutron, have the greatest influence on the different properties found in each atom.
Provide an example of an element.
Gold (Au) is an elemental substance, as its internal content only contains gold atoms.
