Atomic Structure Chemistry Flashcards
what are all substances made up of?
Atoms
what do chemical reactions involve?
the formation of one or more new substances, and often a detectable energy change
what is a mixture?
a combination of two or more elements or compounds not chemically combined together
how can mixtures be separated?
by physical processes, such as:
-filtration
-crystalisation
- simple distillation
- fractional distillation
- chromatography
how did the plum pudding model change?
- the results from the alpha particle scattering experiment led to the conclusion that the mass of an atom was concentrated at the nucleus, which was charged
- Niels Bohr adapted the nuclear model by suggesting that electrons orbit the nucleus at specific distances (theoretical calculations agreed with experimental observations)
what are the charges of the particles in atoms?
- proton +1
- neutron 0
- electron -1
what is the relative mass of each particle in an atom?
- proton 1
- neutron 1
- electron very small
what is the mass number?
the number of protons and neutrons
what is an isotope?
when atoms of the same element have a different number of neutrons
how are elements in the periodic table arranged?
in order of increasing atomic (proton) number
what is a metal?
an element that reacts to form positive ions
what is a non-metal?
elements that do not form positive ions
what are the properties of group 0 elements nobale gases
- unreactive
- do not easily form molecules as they have stable electron arrangements
- eight electrons in the outer shell (except hydrogen)
- boiling point increases with relative atomic mass but still remains low
What is a molecule
a substance made of two or more atoms joined together by a bond
What is a compund
a substance made of at least two different types of atom chemically bonded together
What is a mixture
two or more substances that are mixed together but are not joined by bonds
Define nucleus
the centre part of an atom that contains the protons and neutrons
What was Rutherford’s experiment
the experiment that proved the nucleus must be positively charged (as alpha particles were scattered/deflected by a piece of gold foil)
What is the plum pudding model
a model of the atom that proposed the nucleus was a ball of positive charge with negative electrons embedded in it (we now know this is incorrect)
What is chromatography
a technique commonly used to separate a mixture of dyes in ink
What is crystallisation
a technique used to separate a soluble solid (or salt) from a solution
Define filtration
a technique used to separate an insoluble substance from a solvent (one that does not dissolve)
What is the periodic table
the way in which the elements are organized and classified. Called this because of the regularlly repeating patterns.
Who was John Dalton
the scientist who proposed one of the first periodic tables, he organized the elements in order of atomic weight
Who was John Newlands
the scientist who built on the ideas of Dalton and arranged elements into sets of eight (as he found that each eighth element had similar properties)
Who was Dmitri Mendeleev
the Russian chemist who proposed the periodic table we use today- he left gaps for undiscovered elements.. his table was accepted by scientific community
We’re are metals on the table
the elements found to the left of the periodic table, they are electrical conductors
We’re are alkali metals found
group 1 of the periodic table.
-Melting points and boiling increase going down the group
-react with water to produce hydrogen and metal hydroxide
-reactivity increases down the
We’re are the halogens found
group 7 of the periodic table.
-reactivity decreases as you go down the group
-all form negative ions in their ionic compounds
-form covalent bonds with other non metals
We’re are transition metals found
the middle block of metals in the periodic table, containing elements such as: copper, gold and iron. Compared to alkali metals much higher melting points and densities. Stronger and harder but much less reactive
- they don’t react vigorously with water
-form ions with different charges
- elements and transition compounds form important industrial
reaction of sodium with water
melts to form a ball, fizzes rapidly and may form an orange flame
What are two products formed when an alkali metal reacts with water
metal hydroxide + hydrogen
What is displacement reaction
a reaction in which a more reactive halogen takes the place of a less reactive halogen
