C1 - Atomic Structure & the Periodic Table Flashcards
What is the definition of an element? Give an example
Elements are made from one type of atom (eg. sodium)
What is the definition of a compound? Give an example
Compounds are two or more different elements chemically bonded (eg. sodium chloride)
What is the definition of a mixture? Give an example
Mixtures are two or more elements or compounds not chemically bonded (eg. air)
Name the 3 subatomic particles
Protons, electrons and neutrons
Which particles are found in the nucleus?
Protons and neutrons
Which particle orbits the nucleus on shells?
Electrons
What is the charge of an electron?
-1, negative
What is the charge of a neutron?
0, neutral
What is the charge of a proton?
+1, positive
What is the overall charge of an atom? Why?
Neutral - there are the same number of electrons and protons (they cancel each other out)
How do you work out the number of protons in an atom?
Use the atomic number
How do you work out the number of electrons in an atom?
Use the atomic number
How do you work out the number of neutrons in an atom?
Atomic mass number - atomic number
Which subatomic particle decides what the element is?
The number of protons
What did the plum pudding model suggest the atom was like?
A ball of positive charge with negatively charged electrons scattered in it
What did Rutherford (nuclear) model think the atom looked like?
Positively charged nucleus (small) with electrons surrounding the nucleus
What did Bohr discovery about the atom?
He discovered that electrons went around in shells
State the size of the nucleus
1 x 10-14m
State the size of the atom
1 x 10-10m
What is an isotope?
An element with the same number of protons and electrons but different numbers of neutrons
How are elements organised in the modern periodic table?
According to atomic / proton number
How were elements ordered in the early periodic table?
According to atomic weight
What were the main issues with the early periodic table?
- It had no gaps for undiscovered elements
- Some elements were placed in groups with elements that had very different properties
How are elements in the modern periodic table grouped?
They are grouped according to their properties
Where are metals found on the periodic table?
Left and bottom
What is group 1 called?
Alkali metals
What is group 7 called?
Halogens
What is group 0/8 called?
Noble gases
How many electrons can go on each shell?
1st - 2, 2nd - 8, 3rd - 8, 4th- 18
How are group number and outer electrons number related?
Group number = number of electron on outer shell
How are period number and shell number related?
Period number = number of shells
What are the properties of group 1 metals?
- Conduct electricity, can be cut
- React with water and oxygen
- Low density
How does the reactivity of group 1 elements change down the group?
They get more reactive
Complete the equation:
metal + water > … + …
Metal + water = metal hydroxide + hydrogen
What is the test for hydrogen?
Squeaky pop
How do I test that metal hydroxides are alkali?
Add universal indicator - it will turn purple
Complete the equation:
Metal + oxygen > ……
Metal + oxygen > metal oxide
What is the formula for chlorine?
Cl2 (diatomic)
What is the formula for fluorine?
F2 (diatomic)
What is the colour and state of fluorine at room temperature?
Yellow / green gas
What is the colour and state of chlorine at room temperature?
Green gas
What is the colour and state of bromine at room temperature?
Brown liquid
What is the state symbol for a gas, liquid and a solid?
(s), (l), (g)
Name some properties of noble gases
Low melting points, unreactive
Why are noble gases unreactive?
They have a full outer shell
What is the easiest way to identify whether something is a element?
Look in the periodic table
What is a molecule?
Two or more atoms chemically bonded
What is the mass of a proton?
1
What is the mass of a neutron?
1
What is the mass of a electron?
0
What did Thompson (plum pudding model) suggest the atom was like?
A ball of positive charge with negative electrons scattered in it
Rutherford realised that the plum pudding model was wrong.
What was Rutherford’s model of the atom like?
What did he call his model of the atom?
Rutherford thought the atom was made of a tiny positively charged nucleus, surrounded by scattered electrons.
He called it ‘the nuclear model’
How did Bohr improve Rutherford’s nuclear model of the atom?
Bohr realised that electrons orbit the nucleus on shells
How big is the nucleus of an atom compared to the whole atom?
The nucleus of the atom is 1/10,000 of the size of an atom
Where is most of the mass of the atom found?
In the nucleus, because this is where protons and neutrons are found
How did Mendeleev organise the elements in his periodic table?
Mainly order of relative atomic mass but he changed the order slightly to put elements with similar properties in the same group