Atoms, elements, and the periodic table Flashcards
What does it mean if a compound ends in –ide?
Tells you there is 2 elements
What does a chemical reaction involve?
The formation of one or more new substances; usually with an
energy change
What is the difference between an element and a compound?
Elements contain one type of atom and compounds contain
more than one type
What does it mean if a compound ends in –ate?
Tells you there is 3 or more elements - one is always oxygen
What is the difference between a compound and a mixture?
The substances in a mixture are not chemically bonded together,
but they are in a compound
Describe the method used to collect the salt from a mixture of
sand and salt (Crystallisation)
Add water and stir to dissolve the salt. Use filtration to remove
the sand. Heat the water (gently) to allow the salt to crystallise
(to avoid dryness)
What process is used to purify seawater to obtain usable water?
Simple distillation
Describe how the following equipment is used to separate water and ethanol (fractional distillation)
The ethanol and water mixture are heated. Ethanol has a boiling
point of 78°C and will vaporise first. The gas passes over the
fractionating column and into the condenser. Here it will condense,
turning back into it’s liquid state
Why do the inks separate to produce a chromatogram?
The separation depends on how soluble the chemical is in the
solvent and how strongly the chemical is attracted to the paper
Which subatomic particle did JJ. Thomson discover?
The electron
Describe the plum pudding model
It is a spherical cloud of positive charge with electrons dotted around
Rutherfords experiment
The gold foil experiment
He lined up alpha particles (2 protons, 2 electrons) at gold foil expecting them to go through however some were deflected and didn’t go through
State two ways in which Rutherford’s experiment changed
Thomson’s model of the atom
He said the positive charge was concentrated into very small
volume at centre of atom (nucleus) and the electrons orbit
nucleus
Explain why Bohr revised Rutherford’s model of the atom
Suggesting electrons orbit the nucleus at different distances
Complete the sentence ‘All atoms of one type of element have the
same number of…
Protons
What does the atomic number tell us about an atom?
Number of protons
What does the mass number tell us about an atom?
Number of protons + number of neutrons
How is an isotope different to an atom?
Different number of neutrons
Why is the overall charge of an atom zero?
Number of protons (positive) = number electrons (negative)
How are elements arranged in the modern periodic table?
Increasing atomic number
What does the column an element is in tell you about the atoms?
Number of electrons in outer shell
How were elements classified before the discovery of subatomic
particles?
Arranging in order of their atomic weights
What does the row an element is in tell you about the atoms?
Number of electron shells
What was the problem with early periodic tables?
What was the problem with early periodic tables?
