Chemistry Flashcards
Acid+metal
Salt+Hydrogen
Acid+Metal Oxide
Metal salt+ Water
Acid+ Metal Carbonate
Salt+water+carbon dioxide
H2SO4
Sulfuric acid
HCl
Hydrochloric acid
HNO3
Nitric acid
CH3COOH
Acetic/Ethanoic Acid (vinegar)
H3PO4
Phosphoric acid
Atoms
small indivisible building blocks of life
Periodic table
List of atoms from smallest to largest
Molecules
When atoms stick together, they form clusters known as molecules
Element
a substance made up of many of the same atoms
Molecular element
A substance made up of the same molecules
Compound
a substance made up of molecules or a lattice with different types of atoms
Why do the electrons orbit the protons
They are electrically attracted to one another (negative charge in electrons attracted to positive charge in protons)
Atomic number
number of protons and electrons in the atom
Mass number
Total number of neutrons and protons in the nucleus
Isotopes
Atoms of the same element with different numbers of neutrons and different masses.
Electron configuration
no. of electrons in each shell of an atom
e. g. Carbon: 2,4
Electrons can move
Electrons in atoms can move and jump up and down between electron shells
this movement creates light
example: fireworks
Cation
When an electron is removed from an atom and it becomes positively charged
Anion
When an electron is added to an atom and it becomes a negatively-charged ion
Ionic compounds
When anions and cations come together, they form compounds called ionic compounds
Acids
Corrosive substances meaning they react with solid substances, eating them away
Bases
have a bitter taste and feel slippery or soapy to touch
Some bases are very corrosive
Alkalis
Bases that can be dissolved in water
What is an acid-base indicator for
Used to tell whether a substance is an acid or a base
the indicators react with acids or bases, producing a different colour in each
Litmus paper
turns red in an acid
turns blue in a base
bromothymol blue
turns yellow in acid
bluish-purple in base
PH Scale
Numbers on a pH scale show how acidic or basic a substance is
0-7 means acidic
7-14 means basic
7 means neutral
Democritus
Suggested that all substances consisted of tiny indestructible particles called atoms
John Dalton
Atomic theory
all matter consists of atoms
atoms are indivisible
atoms of the same element are alike
J.J. Thompson
Plum pudding model
Atoms were positively charged spheres with negatively charged electrons embedded in them
Lord Rutherford
consisted mostly of empty space with a dense nucleus containing protons
electrons orbited the shell but would eventually lose energy and spiral in towards the nucleus
Niels Bohr
Electrons orbit the nucleus at different energy levels
Only electrons with a specific amount of energy could exist at each level
electrons could only move from one level to another by losing or gaining energy
Sir James Chadwick
discovered that the nucleus also contained neutrons
Rutherford’s experiment
He fired alpha particles at a thin sheet of gold foil. Most of the particles went through but few were reflected back. This showed that the atoms in the gold consisted of mostly empty space.
Stable or unstable
Stable- in some atoms, the protons and neutrons found in the nucleus are held together very strongly
Unstable- in some atoms, the protons and neutrons are not held together strongly, meaning they decay to form other elements. These are radioactive and called radioisotopes
Alpha particles
cannot travel easily through materials
can be stopped by a sheet of paper or human skin
cause little hazard to external body but can cause serious damage if breathed in
Beta particles
can penetrate human skin and damage living tissue, but cannot penetrate thin layers of plastic, wood or aluminium.
Gamma rays
not particles but bursts of energy released after alpha or beta particles have been emitted.
travel at the speed of light and highly penetrating
Can cause serious or permanent damage to living tissue and can be stopped only by a thick shield of lead or concrete
Nuclear radiation
energy emitted from the nucleus of radioactive substances
Brownian motion
Robert Brown noticed that pollen grains jiggled around in water. He didnt know why
Einstein realised that this was because of water molecules hitting the tiny pollen grains
Gamma decay
when a nucleus has excess energy so a gamma ray is emitted form the nucleus
Alpha decay
When the nucleus is too large so an alpha particle is emitted to reduce the size of the nucleus
Beta decay
When the nucleus has too many neutrons relative to protons. Neutron changes into a proton and emits an electron
Ionic compound
Formed when atoms of metals or non-metals come together and lose or gain electrons and become ions
Polyatomic ions
ions made up of more than one type of atom
Acid + Base
Salt+Water
