P1 - Atomic Structure and Periodic Table Flashcards
What is the radius of an atom ?
About 0.1 nano meters (1 × 10^-10 m)
What is the nucleus of the atom ?
The middle, containing the protons and neutrons and is where both the mass and positive charge of an atom is concentrated. With a radius of 1 × 10^-14 m.
What is the atomic number of an atom ?
The number of protons (= number of electrons).
What is the mass number of an atom ?
Number of protons + number of neutrons.
How do you calculate the number of neutrons ?
Mass number - atomic number.
Why does an atom have a neutral charge ?
It has an equal number of electrons and protons, cancelling out each others charge.
What is an ion ?
An atom that has lost or gained electrons, meaning it has an overall charge where protons doesn’t equal electrons.
What is an element ?
A substance made up of atoms that all have the same number of protons in their nucleus.
What are the characteristics of an electron ?
Move around the nucleus in shells, negatively charged and tiny with virtually no mass, but cover a lot of space, the volume of their orbits determines the size of the atom.
What subatomic particle determines an atoms element ?
The proton, the number of electrons can change to form ions and the number of neutrons can change to make isotopes.
How many different elements are there ?
Roughly 100.
What are isotopes ?
Different forms of the same element, which have the same number of protons but a different number of neutrons.
What is relative atomic mass ?
An average mass taking into account the different masses and abundances of all the isotopes that make up the element.
How do you work out the relative atomic mass of an element ?
Sum of (isotope abundance × isotope mass number) ÷ sum of abundances of all the isotopes
What are compounds ?
Substances formed from two or more elements, the atoms of each are in fixed proportions throughout the compound and they’re held together with chemical bonds.
