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Where is the Nucleus of an atom?

In the middle of the atom


What makes up the nucleus of an atom?

Protons and Neutrons


What is the overall charge of the nucleus of an atom?

It has an overall positive charge, as there aren't any electrons which have negative charges


Where is most of the mass of an atom found?

In its nucleus


How big is the size of the nucleus of an atom compared to the atom as a whole?

Very small


Electrons.... Are they stationary?

No, they move about the nucleus, orbiting it


What charge do electrons have?

A charge of -1


The charge of an electron is equal but opposite to the charge of a proton.
True or false



How big are they compared to the size of the nucleus?

They are tiny compared


The size of the orbit of the electrons don't determine the size of the atom.
True or false



How much mass do they have?

A negligible amount


Where are they found?

In the electron shells of an atom


What charge do neutrons have?

An overall neutral charge


Is the charge of a neutron equal to the charge of an electron?

No, it has a charge of naught, no charge


The number of protons is equal to the number of electrons.
True or false

The overall charge of an atom has to be stable, at no charge, this means that the protons have to be of equal number to the electrons in order to keep the overall charge equal


The number of neutrons isn't fixed, but is usually about the same as the number of protons.
True or false



Are protons:
a) Heavy and neutrally charged
b) Tiny and neutrally charged
c) Heavy and positively charged

c) Heavy and positively charged


Are neutrons:
a) Heavy and neutrally charged
b) Heavy and positively charged
c) Tiny and negatively charged

a) Heavy and neutrally charged


Are electrons:
a) Heavy and neutrally charged
b) Heavy and negatively charged
c) Tiny and negatively charged

c) Tiny and negatively charged


What do electrons always occupy?

Electron shells


The highest energy levelled electron shells are always filled first
True or false

False, lowest energy level shells are always filled first


1st shell: 2 electrons
2nd shell: 8 electrons
3rd shell: 8 electrons

True or false



Atoms are much sadder when they have a full electron shell

True or false

False, they are much happier when they have a full electron shell


In most atoms, the outer shell is not full. This makes the atom want to react.
True or false



The rules to working out electron configurations:
Nitrogen has 7 protons... So it must have seven electrons
The first shell can take a maximum of 9 electrons and the second can only take a maximum of 10 electrons.
So the electronic configuration of nitrogen is 2.5

Incorrect, the first shell can hold a maximum of 2 electrons, and the second can only hold 8 electrons, making the configuration of the electrons of nitrogen 2.5


Elements consist of how many types of atoms?



Each element has different numbers of protons.
Does this mean that is has the same number of electrons?



For example, any atom of the element helium will have 2 protons, therefore any atom with 2 protons will be a helium atom

Yes, it will


What does the atomic number of an atom say?

How many protons there are in that atom


Is the atomic number the same for all elements?

No, it is unique to each individual element


The atomic number also tells you the number of electrons there are

Yes, because an atom has the same number of protons and electrons in an atom


The atomic mass is usually double the number of the atomic number, why?

Because the atomic number represents the number of protons, which is usually the same as the number of neutrons, and those two subatomic particles both have a mass of 1. Electrons barely have any mass, and are not worth considering in this situation


Explain what is meant by the term isotope:

Isotopes are: different atomic forms of the same element, which have the same number of protons but different number of neutrons


Isotopes must have the same number of protons but have different mass numbers



If isotopes had different numbers of protons, should they be different elements altogether?

Yes, as the number of protons determines what the element is


Popular pairs of isotopes:
Carbon-12 How many electrons does this have?
Carbom-14 How many protons does this have?

Carbon-12 has 6 electrons,
Carbon-14 has 8 protons.

What is different is the number of neutrons


What is the relative atomic mass of an element judged by?

It is judged by the average mass of the isotopes of the element


Relative abundance means how much there is of each isotope compared to the total amount of the element in the world.
Can it be a ration, fraction, or a percentage?

It can be all three


Work out the relative atomic mass of chlorine

Ar = ((35*3)+(37*1)) / 3+1 = 35
So the Ar (relative atomic mass) of chlorine is 35.5


How do you work out the relative atomic mass of an atom?

First, multiply the mass of each isotope by its relative abundance, then ad those together. Finally, divide the sum by the sum of the relative abundances


Why is the Ar of an element usually rounded to a whole number?

Because usually the Ar of an element is either not an easy decimal, or not a whole number


Did the scientists in the 1800's know about the structures of atoms?

No, they didn't have the technology to do so?


When did the scientists begin to realise periodic patterns in the properties of the elements?

When they arranged the elements in the order of their relative atomic masses.


Give an example of a pattern in the atoms when ordered in order of their relative atomic masses

The pattern of seeing the very reactive metals that make an alkaline solution when placed in water at regular intervals in the list.


How did Dimitri Mendeleev arrange the elements to make his version of the periodic table?

He arranged the 50 or so elements which were known into a periodic table which was ordered according to the properties of their compounds. He placed elements with similar chemical properties in the same vertical groups, but he had to leave gaps in his table, as some ee nets had not yet been discovered.


Why were the gaps in Mendeleev's periodic table clever?

Because they predicted the properties of new, undiscovered elements.


Have the new elements been found yet?

There are still more to find, we just need more precise and powerful machines to work with, to produce these undiscovered elements in


Why has a whole new set of elements been found?

These elements have properties which make them invisible to the naked eye, and they can't be reacted with other elements either. Scientists have only just developed the ability to detect them.


How long ago did the major refinements to the table start?

About a hundred years ago