questions Flashcards
in a chemical reaction the substances that react with eachother are called the …..
reactants
give an example of diffusion
A tea bag immersed in a cup of hot water will diffuse into the water and change its colour. A spray of perfume or room freshener will get diffused into the air by which we can sense the odour.
two factors that affect denisty
temp and change of state
the nuculeus of an atom is made up of
positively charged subatmoic particles called protons
name the three main groups in which elements on the periodic table are arranged
metals nonmetals and metaloids
the lowest temp
273 degrees/o kelvins
the formula to work out density
density=mass/volume
work out volume
v=lxbxh
reading of a triple beam balance
add up all the numbers
bohr diagram
find number of protons and neutrons find protons by looking at number on top and neutrons by top minus bottom number
how to work out atomic mass
protons plus neutrons
work out electrons
number at the bottom
protons and neutrons are also known as
nucelons
why are atoms electrically neutral
because the electrons are the same as protons
name an element in group 1
lithium
describe the difference between an element and a compound
Elements are pure substances which are composed of only one type of atom. Compound are substances which are formed by two or more different types of elements that are united chemically in fixed proportions.
daltons model
matter is made up of small basic particles
thomsons model
atom is a solid sphere with positive and negative charges
rutherford model
proposed that the negatively charged electrons surround the nucleus of an atom.
chadwick
discovered neutrons
atomic number
smaller number
resultant vector
A resultant vector is the vector sum of two or more individual vectors.
res
