C1 Flashcards
What is on the left of the steps in the periodic table?
Metals
What is on the right of the steps on the periodic table?
Non metals
What is an element?
A small substance that is made up of only one type of atoms
What are vertical columns in a periodic table called?
Groups
What are the horizontal rows in a periodic table called?
Periods
What is the law of conservation of mass?
The total mass of the products formed in a reaction is equal to the total mass of the reactants
What is on the left and what is on the right hand side of a word equation?
Reactants on the left
Products on the right
What are the state symbols for liquid, solid, gas and aqueous ?
(L) , (s) , (g) , (aq)
Why should all symbol equations be balanced?
Because atoms cannot be created or destroyed
What is a mixture?
Made up of 2 or more substances that are not chemically combined together
What are the differences between compounds and mixtures?
-compounds have a fixed composition mixtures don’t
-chemical reactions must be used to separate the elements in a compound but in a mixtures u can separate using physical techniques
-there are chemical bonds in a compound and there are no chemical bonds in a mixture
Name ways u can separate substances in a mixture?
-filtration
-distillation
-chromatography
-crystallisation
What is fractional distillation used for separating?
Miscible liquids
What is the atomic number?
The number of protons in each element
What is the mass number?
The number of protons and neutrons in the nucleus of an atom
How do u find the number of neutrons?
Number of neutrons=mass number of - atomic number
What is an ion
an atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons
What is an isotope?
forms of an element that have the same number of protons but different numbers of neutrons
What is the electronic structure?
When you write down the numbers in each energy level
What is an atom?
An atom is the smallest part of an element that can exist
What is a compound?
A pure substance made from more than one type of element chemically combined in a fixed proportion.
What do chemical reactions always involve?
The formation of one or more new substances and often involve a detectable energy change
How do you separate compounds?
Compounds can only be separated by chemical reactions
Who discovered the electron?
J.J. Thomson
Who discovered protons and the nucleus in an atom?
Ernest Rutherford
Who discovered neutrons?
James Chadwick
What is the radius of an atom?
0.1nm
What are the relative masses of protons , neutrons and electrons
Proton-1
Neutron-1
Electron-very small
Describe the alpha particle scattering experiment?
What did the plum pudding model suggest?
It suggested that the atom is a ball of positive charge w negative electrons embedding it
What conclusion did the alpha scattering experiment lead to?
That the mass of an atom was concentrated at the centre and that the nucleus was charged
How did niel Bohr adapt the nuclear model?
By suggesting that electrons orbit the nucleus at specific distances
What did the positive charge of the nucleus be divided into?
It could be subdivided into a whole number of smaller particles,each particle having the same amount of positive charge. The name proton was given to these particles
What did James Chadwick’s experiments provide?
It provided the evidence to show the existence of neutrons within the nucleus
How are the elements in the periodic table arranged?
In order of atomic number and so elements with similar properties are in columns,known as groups
What do elements in the same group have ?
The same number of electrons in the outer shell and this gives them similar chemical properties
How were elements arranged before the discovery of protons neutrons and electrons ?
By arranging them in order of their atomic weight
What was wrong with the early periodic table?
It was incomplete and some elements were placed in inappropriate groups if the strict order of atomic weights was followed
How did Mendeleev overcome some of the problems?
By leaving gaps for elements that he thought had not been discovered and in some places changed the order based on atomic weights
What filled the filled gps in Mendeleev periodic table ?
Elements with properties predicted by Mendeleev
What did the knowledge of isotopes do?
They made it possible to explain why the order based on atomic weights was not always correct
What is the atomic number?
The number of protons in an element
What are non metals ?
Elements that do not form positive ions
What are the majority of elements?
Metals
What are the elements in group 0 called ?
Noble gases
What are properties of noble gases?
They are unreactive and do not easily form molecules because there atoms have stable arrangements of electrons
How many electrons are there on the outer shell of noble gases?
8 expect from helium which has 2
What happens to the boiling points of noble gases?
They increase with increasing relative atomic mass
What are the elements in group 1 known as ?
Alkali metals
How many electrons are there in the outer shell of alkali metals?
1
What is the reactivity of alkali metals?
It increases as it goes down the group
What are the elements in group 7 known as ?
Halogens
Why do halogens have similar reactions.
Because they all have 7 electrons in their outer shell
What are the halogens.
They are non metals and consist of molecules made of pairs of atoms
In group 7 what happens when u go down the group?
The further down the group an element is the higher its relative molecular mass , melting point and boiling point and the reactivity decreases going down
What can a more reactive halogens displace?
They displace a less reactive halogen from an aqueous solution of its salt
What are transition metals?
They are metals with similar properties which are different from those of the elements in Group 1
What do many transition metals have?
They have more than one ions and they form coloured compounds and are useful as catalysts
What are the properties of alkali metals (group 1)?
- low in density and they are soft metals
- they form 1+ ions as they have 1 electron in their outer shell
What are the trends of alkali metals?
Increasing reactivity- the attraction between the nucleus and electron decreases because the electron is further away from the nucleus
Lower melting and boiling points
Higher relative atomic mass
What are the properties of metallic bonding ?
-very strong
-high melting and boiling point
-conduct electricity and heat
What are the properties of covalent bonding?
-high melting and boiling point
-very strong
-does not conduct electricity
What are the properties of ionic bonding?
-very strong
-high melting and boiling point
-when liquid it conducts electricity when it’s solid it does not conduct electricity
