Atomic structure Flashcards
What is an atom?
Everything in the world is made up of atoms. The structure of the atom is what gives an element its chemical and physical properties
What is an electron?
Negatively charged particles that spin around the positive centre of the atom in circles called energy levels. Their mass is so small it is nearly zero.
What is a proton?
Positively charged particles that are contained in the nucleus of the atom (the centre) they have a mass of 1 amu (atomic mass unit).
What is a neutron?
Particles with no charge that are also contained in the nucleus of the atom. They also have a mass of 1 amu.
What is an electrons mass, charge and location?
Mass- approx 0
Charge- (-1)
Location- energy level
What is a protons mass, charge and location?
Mass- 1 amu
Charge- +1
Location- nucleus
What is a neutrons mass, charge and location?
Mass- 1 amu
Charge- 0
Location- nucleus
How are the elements arranged in the periodic table?
The chemical elements are arranged in order of increasing atomic number
What are the labels on a periodic table?
The horizontal rows are called periods and the vertical rows are called columns
Alkali metals
The elements in group 1 are known as alkali metals. They react rapidly (very fast) with water, producing an alkaline solution and hydrogen gas. The metals become more reactive as you go down the group
Halogens
The elements in group 7 are known as halogens. Fluorine and chlorine are gases. Bromine is one of only two liquid elements. Iodine is solid. They exist as diatomic molecules - they have two atoms in each molecule. As you go down the group the halogens become less reactive
Nobel gasses
The elements in group 0 are known as noble gases. They are very unreactive and exist as individual atoms (monatomic).
Transition metals
The transition metals are elements which are found between groups 2 and 3. Well known examples are iron, copper and gold. They are generally quite dense (heavy) and many form brightly coloured compounds
What does the atomic number of an element tell you?
The atomic number of an element tells you how many protons that the element has. This is written at the bottom left hand side of the symbol.
Mass number
The mass number is given at the top left of the elements symbol, for example, sodium has a mass number of 23
The mass number of an element tells us the number of protons AND neutrons in an atom (the two particles that have a measurable mass).
Sodium has a mass number of 23amu. Since sodium has 11 protons, the number of neutrons must be 23 – 11 = 12 neutrons.
