C3 - Atoms, Elements and compounds Flashcards
An atom is made up of a
positively charged nucleus surrounded by negatively charged electrons
The atomic number is the number of
protons in an atom of a particular element
The mass number of an atom is
the number of protons and neutrons found in a nucleus
What is the mass and atomic number of sodium
Mass number = 23
Atomic number = 11
What sub atomic particles make up the nucleus
protons and neutrons
Difference between physical and chemical changes
Physical changes change the appearance of a substance and not the chemical composition whilst in a chemical change one or more new substances are produced.
What experiment shows that some chemical changes can be reversed
Hydrated blue copper sulfate crystal test
When heated a white powder will form (anhydrous copper sulfate) and water is lost as steam. If water is added it turns blue.
What is the relative mass of protons, neutrons and electrons
proton = 1 neutron = 1 electron = 1/2000
Another name for mass and atomic number
nucleon number (for mass) and proton number (for atomic)
Hydrogen has a proton and electron but no
neutron
In an atom the number of protons is equal to the
number of electrons
In a periodic table the elements are arranged via
their atomic number
Atoms have no
overall charge
When an atom becomes charged due to losing or gaining electrons it is called an
ion
If atoms lose one or more electrons in outer shell its called a
positive ion
If an atom gains one or more electron in outer shell its called a
negative ion
What is an isotope
A same element atom with same number of protons but different number of neutrons
Isotopes have the same properties as their regular atoms because
they have the same number of electrons in the outer shell
A nuclide is a
type of isotope that is characterized due to its distinct specific nucleus
Electrons have fixed positions in atoms called
electron shells
What is the electron configuration of an atom
2 electrons max on the first shell
then it’s 8 max on the next shell after that.
The closer a shell is to the nucleus of an atom
the lower its energy level is