C1-Atomic Structure And C2-Periodic Table Flashcards
What is an atom
the smallest part of an element that can still be recognised as that element
What is an element?
A substance which is made up one atom and cannot be broken down.
What are compounds
Compounds are two or more elements chemically combined in fixed proportions and can be represented by formulae using symbols of the atoms.
How can compounds be seperated
Chemical reactions
What is a mixture
A mixtures consists of two or more elements or compounds not chemically combined together.The chemical properties of each substance in the mixture are unchanged.
The first development of the atom
John dalton-start of 19th century-atoms were described as solid spheres
2nd part of history of atoms
JJ thomson-1897-plum pudding model-the atom is a ball of charge with electrons scattered.
3rd advancement of history of atoms
Ernest rutherford-1909-nuclear model-alpha scattering experiment-mass concentrated at the centre;the nucleus is charged.Most of the mass is in the nucleus.Most atoms are empty space.
4th of history of atoms
Niels Bohr-1911-planetary model,electrons are in shells orbiting the nucleus.Specific distance from nucleus
Last of history of atoms
James chadwick-1940-discovered that there are nuetrons in the nucleus
How the ernest rutherford experiment worked
A beam of alpha paeticles projected at a gold foil,the gole foil surrounded by flourescent screen to detect alpha particles.Most of the alpha particles passed through but some were deflected by the centres of the metal atoms and a tiny bumber were repelled.Suggesting the nucleur model(the nucleus in middle with electrons in around)
What is the atomic number
The number at the bottom which shows the number of protons and electrons.
Mass number
The sum of the protons and nuetrons in an atom
Isotopes
Atoms of the same elements with different numbers of nuetrons
What isrelative atomic mass
An average value that takes account of the abundance of the isotopes of the element.
How to calculate relative atomic mass
(Isotope 1 times abundance) +(isotope 2 times abundance) divided by 100
What is the periodic table
an arrangement of elements in the order of their atomic numbers, forming groups and periods
How was john new lands periodic table like
Ordered his table in order of atomic weight,Worked in law of octaves but this broke down
How did dmitri mandeleevs periodic table work
It was ordered in order of atomic mass but not always strictly in some places he changed the order based on atomic weights.Left gaps for elements that were not discovered
What are metals
Elements that react to form positive ions-found at left of periodic table
What are non metals
Elements that do not form positive ions-found at right and top of periodic table
Characteristics of alkali metals
They react with oxygen to create oxide,they all readt with chlorine to form a white percipitate,the reactivity increases going down the group.There melting and boiling point decreases going down the group
How does lithium react with oxygen
Burns with a strongly red tinged flame and produces a white solid
How does lithium react with water
Fizzes,disappears gradually