Atomic structure Flashcards
Key concepts in chemistry
abundance
Definition
If there is a lot of something, it is described as being abundant.
atom
Definition
The smallest part of an element that can exist.
atomic number
Definition
The number of protons in the nucleus of an atom. Also called the proton number.
charge (electrical)
Definition
An imbalance of electrons and protons in a material. An excess of electrons results in negative charge, a deficit of electrons results in positive charge.
electron
Definition
Subatomic particle, with a negative charge and a negligible mass relative to protons and neutrons.
element
Definition
A substance made of one type of atom only.
isotope
Definition
Atoms of an element with the same number of protons and electrons but different numbers of neutrons.
mass
Definition
The amount of matter an object contains. Mass is measured in kilograms (kg) or grams (g).
mass number
Definition
The number of protons and neutrons found in the nucleus of an atom.
neutral atom
Definition
An atom in which the number of protons and electrons is the same.
neutron
Definition
Uncharged subatomic particle, with a mass of 1 relative to a proton. The relative charge of a neutron is 0.
nuclei
Definition
Nuclei is the plural of nucleus. The nucleus is the central part of an atom. It contains protons and neutrons, and has most of the mass of the atom.
nucleus
Definition
The central part of an atom. It contains protons and neutrons, and has most of the mass of the atom. The plural of nucleus is nuclei.
particle
Definition
A general term for a small piece of matter. For example, protons, neutrons, electrons, atoms, ions or molecules.
properties
Definition
The characteristics of something. In chemistry, chemical properties include the reactions a substance can take part in. Physical properties include colour and boiling point.
proton
Definition
Subatomic particle with a positive charge and a relative mass of 1. The relative charge of a proton is +1.
relative atomic mass
Definition
The mean relative mass of the atoms of the different isotopes in an element. It is the number of times heavier an atom is than one-twelfth of a carbon-12 atom.
relative mass
Definition
The relative mass is the number of times heavier a particle is, compared to another.
subatomic particle
Definition
Objects found in atoms, including protons, neutrons and electrons.
What is Dalton’s model
overview
John Dalton published his ideas about atoms in 1803. He thought that all matter was made of tiny particles called atoms, which he imagined as tiny solid balls.
Dalton’s model included these ideas:
atoms cannot be broken down into anything simpler
the atoms of a given element are identical to each other
the atoms of different elements are different from one another
during chemical reactions atoms rearrange to make different substances
Dalton’s model has changed over time due to what?
The Dalton model has changed over time because of the discovery of subatomic particles.
What was discovered in 1897?
Electrons
What was discovered in 1909 -1911?
Atoms have a nucleus with electrons around it
What was discovered in 1913
Electrons occupy shells (energy levels)
What was discovered in 1918?
Protons
What was discovered in 1932?
Neutrons
As a result of the discoveries of: Electrons; Atoms having a nucleus with electron around it; Electrons occupy shells (energy levels); Protons; Neutrons, we know know what?
atoms can be broken down into three smaller particles: protons, neutrons and electrons
atoms of an element have identical numbers of protons and electrons, but can have different numbers of neutrons
atoms of different elements have different numbers of protons and electrons
Atoms can be broken down into what?
atoms can be broken down into three smaller particles: protons, neutrons and electrons
Atoms of an element
Number of protons, electrons and neutrons
atoms of an element have identical numbers of protons and electrons, but can have different numbers of neutrons
Atoms of different elements have different numbers of what?
atoms of different elements have different numbers of protons and electrons