C1- Atomic Structure and the Periodic Table Flashcards
Can you see atoms with a microscope?
No they are too small
What do atoms contain?
Protons ,neutrons and electrons
Where is the nucleus in the atom?
Middle
Where are the protons and neutrons within the atom?
The nucleus
What charge does the nucleus have?
Positive
How much of the mass of the atom is concentrated in the nucleus?
Almost all of it
What do electrons move around the nucleus in?
Electron shells
What charge do electrons have?
Negative
What changes the volume of the electrons orbit?
The size of the atom
How much mass does the electron have?
Virtually none
How many more electrons does an atom have than protons?
None
What charge do atoms have and why?
Neutral ,they have the same number of protons and electrons
In an ion does the number protons equal the number of electrons?
No
What number on each element on the periodic table describes the element?
Atomic number and mass number
What does the atomic number tell you about an atom?
How many protons there are
What does the mass number tell you about an atom?
The total number of protons and neutrons in the atom
How to get the number of neutrons?
Subtract the atomic number from the mass number
What is an element?
A substance made up of atoms that all have the same number of protons in their nucleus
How many different atomic numbers do the atoms have within the elements?
They are all the same
What within the atom nucleus determinants what type of atom it is?
The number of protons
What is a substance called if it only contains atoms with the same number of protons?
Element
How many different elements are there (roughly)?
100
What are isotopes?
The same as elements apart from extra neutrons
Do isotops have the same number of protons as the element?
Yes
Because elements can exists a number of different isotopes what is used instead of mass number?
Relative atomic mass
What is relative atomic mass?
An average mass taking into account the different masses and abundances (amounts) of all the isotopes that make up the element
What is the formula for working out the relative atomic mass of an element
relative atomic mass=sum of(isotope abundance x isotope mass number/sum of abundances of all the isotopes
What do atoms join together to make?
Compounds
What are compounds?
Substances formed from two or more elements, the atoms of each are in fixed proportions throughout the compound and they’re held together by chemical bonds
How do atoms make bonds?
Give away, take or share electrons
Are the nuclei effected by bonds made in atoms?
No
What needs to happen to separate the original element of a compound ?
A chemical reaction
What type of substance is made from a non-metal and metal?
An ion
When forming an ion does the metal loose electrons or loose them?
Loose
What does a compound made from non-metals consist of?
Molecules
What is covalent bonding?
Each atom shares an electron with another atom
Are the properties of a compound normally similar to the original element?
No
How are chemical changes shown?
Using chemical equations
Do symbol equations show the atoms on one side?
No ,both
Do symbol equations need to be balanced?
Yes
Can mixtures be easily separated?
Yes
Are there any chemical bonds between different elements in a mixture?
No
Can elements and compounds be part of a mixture?
Yes
How can u separate mixtures?
Physical methods
Name four examples of physical methods to separate mixtures?
- Filtration
- Crystallisation
- Simple distillation
- Fractional distillation
- Chromatography
Is air a mixture, element or compound?
Mixture
What elements are in the air?
- Nitrogen
- Oxygen
- Carbon dioxide
- Argon
What is in crude oil?
A mixture of different length hydrocarbon molecules
Are the properties of mixture just a mixture of the properties of the separate parts?
Yes
When did John Dalton have theory of the atom?
The start of the 1800s
What was John Dalton’s theory of the atom?
He described atoms as a solid spheres and said that different spheres made up the different elements
What scientist had a theory on the atom in 1897?
J J Thomson
What was JJ Thomson’s theory of the atom?
- Atoms weren’t solid spheres
- He showed the atoms could contain even smaller negatively charged particles-electrons
- he came up with the plum pudding model
What did the plum pudding model show?
The atoms as a ball of positive charge with electrons stuck in it
Who showed that the plum pudding model was wrong?
Ernest Rutherford
When was it shown that the plum pudding model was wrong?
1909
What experiment showed the plum pudding model was incorrect ?
Alpha particle scattering experiment
What was the alpha particle scattering experiment?
Ernest Rutherford and his student Ernest Marsden fired positively charged alpha particles at extremely thin sheet of gold
What were the people conducting the alpha particle scattering experiment expecting to happen based on the plum pudding model?
The particles to go straight through or be slightly deflected at most
What did the particles do in the alpha particle scattering experiment?
- Some deflected backwards ( more than expected)
- Most went straight through
- A small number deflected backwards
What was Ernest’s Rutherford particle model called?
The nuclear model
What is the nuclear model?
There is a tiny positive positively charged nucleus in the centre, where most of the mass is concentrated. A ‘cloud’ of negative electrons surrounds this nucleus- so most of the atom is empty space .
Who realised that Ernest Rutherford’s model was incorrect?
Niels Bohr
Why did the scientist realise that Ernest Rutherford?
If there were a cloud of electrons they would be attracted to the nucleus causing the atom to collapse?
What new thing did Niels Bohr’s model have?
Shells and the electrons orbit the nucleus in fixed shells and aren’t anywhere in-between. Each shell in a fixed distance from the nucleus.
Was Neil Bohr’s model supported by experiment ?
Yes
Who showed there were protons?
Rutherford
How many years after scientists said there was a nucleus in an atom did a scientist come up with the idea that there are neutrally charged particles?
20
Who first said there neutrons?
James Chadwick
What are five electron rules?
-Electrons always occupy shells (sometimes called energy levels)
-The lowest energy levels are always filled first - these are the ones closest to the nucleus
-Only a certain number of electrons are allowed in each cell:
1st shell: 2 2nd shell: 8 3rd shell: 8
-Atoms are much happier when they have full electron shells- like the noble gases
-In most atoms, the outer shell is not full and this makes the atom want to react to fill it
What number in the first 20 elements tells you the number of protons?
Atomic number
How were elements arranged in the 1800s?
By atomic mass
Until recently what were the 2 obvious ways to categorise elements?
- Their physical and chemical properties
- Their relative atomic mass
When did scientists realise that they could arrange elements by atomic number?
After they discovered protons neutrons and electrons. 20th century
What were the issues with early periodic tables?
- They were not complete
- Some elements were placed in the wrong group
What did Dmitri Mendeleev do that was special when creating his periodic table?
He left gaps
In what year did Dmitri Mendeleev create his first periodic table ?
1869
How many elements were in Dmitri Mendeleev original periodic table?
50
How did Dmitri Mendeleev mainly order the elements?
In order of atomic mass
When were isotopes discovered?
20th century
What is the main reason for how elements are laid out?
Increasing atomic (proton) number
Which side of the periodic table are metals on?
left
How are elements with similar properties laid out on the periodic table?
They are in columns
What are the vertical columns called?
Groups
What does the group number tells you?
The number of electrons in the outer shell
What is the exception for the group number telling you what it tells you?
Group 0
How can you predict what the properties of one element knowing the properties of another?
If they are in the same group they have similar properties
What are rows called in the periodic table?
Periods
What do the periods tell you in the periodic table?
Each new period is another full shell of electrons
Are most elements non-metals?
No
What charge ions do metals form?
Positive
Do non-metals generally from positive ions?
No
Does the electron structure affect how the atom will react?
Yes
How do atoms generally react to form?
A full outer shell
How do atoms from a full outer shell?
- Losing
- Gaining
- Sharing
If the outer shell is close to being shell how is an ion formed?
By getting to a full outer shell
Do all metals have a metallic bonding?
Yes
Are metals malleable?
yes