Can you help me with a gcse chemistry question please?

[ihatethecold]

I have no clue about this one. I need to be able to explain it to my dd not just have the answer if possible.
Thanks

She needs to find the definitions of atomic number and mass number. That should get her off to a good start.

The atomic number is the number of protons, ie what defines the atom as an atom of gold. Therefore an atom of gold always has 79 protons.

In a neutral atom, the number of protons and electrons are the same, so there are also 79 electrons.

The mass number is the total mass of each atom. For the purposes of this question, an electron has a mass of zero, and the number of neutrons is the difference between the mass number and the atomic number 197 -79 = 118.

Atoms are made up of proton and neutron in the nucleus and electrons in shells. Same amount of protons and elections. This is the little number. Big number gives protons + neutron. So to find amount of neutrons do big number take away small number. Can't see the numbers to give the sum but you should get the idea.

As above, learn what an atomic number and mass number is.

Atomic number is both its proton number and electron number, therefore it has 79 protons and 79 electrons

Mass number is the sum of protons and neutrons

Therefore
Protons+Neutrons=197
79+neutrons=197
Neutrons=118

Atomic number is bottom number and is usually called atomic(proton) number. A reminder of this will be clearly visible in the periodic table in the exam.

So protons is 79

Protons are ppppp positive but atoms are neutral there are also 79 negative particles aka electrons orbiting the nuclues.

The neutrons are the large number minus the small number.

For the sand and salt you would add water to dissolve the salt then filter the mixture to remove sand. By evaporating the water you can get the salt back. This is how gandhi started his protest of british rule ( making salt from sea water).

Bitsize or similar go through this in more detail if needed.

Thanks. It’s like gobbledygook.
Even reading the responses don’t make any sense to me.
The question regarding the atoms only the info in the sentence. There is no further info.

We will look into the definitions of atomic number and mass number.

The question tells you that Gold has -
atomic number of 79
mass number of 197

Now, if you learn that the 'atomic number means the proton and electron number'
There is always the same number of protons and electrons.
Therefore the proton number and electron number for Gold is 79.

Now, if you learn that the 'Mass number = Protons+Neutrons'
Mass number of Gold 197
So
197=Protons + Neutrons
197=79 (as you have already worked out above) + Neutrons
Do the maths
197=79 + 118
Neutrons=118

In any stable atom, the number of protons in the atom core (positive charge) will equal the number of circling electrons (negative charge). The atomic number gives the number of protons and hence by extension the number of electrons also. However, the larger of the two numbers, the atomic weight, is a combination of the weight of protons in the core along with neutrons (electrons have no mass as far as atomic weights are concerned). Neutrons have no charge and allow positively-charged protons to exist in near proximity by slotting inbetween the positive protons (otherwise, it would be like trying to push the same polarity end of two magnets together). Unlike electrons, there can be more neutrons than protons and the number can vary up and down compared to the proton total. Two atoms of the same substance with different neutron totals are known as isotopes (this may also come up in a GCSE chemistry question).

The question regarding the atoms only the info in the sentence. There is no further info.

Students are expected to know what the atomic number and mass number refer to. You won’t find that in the question.

BBC bitesize is a good source of information with some good little videos and practice questions.

Yes, go to BBC Bitesize to learn what an atomic number and atomic weight are - it sounds as if she missed/didn’t pay attention in that lesson

In any stable atom, the number of protons in the atom core (positive charge) will equal the number of circling electrons (negative charge

It’s important to be precise about vocabulary. For example, uranium isotopes are unstable-they decay giving out radioactivity. All uranium isotopes have 92 protons and 92 electrons. That doesn’t make them stable.

Atomic weight is incorrect terminology. It needs to be the atomic mass.

Thank you. She missed lots of school the last 3 years and has only just managed to get back in this September for year 11.
We are trying to help her fill gaps.

Might it be worth thinking about a tutor? I used to work with teens in exactly your daughter’s position.

Really good luck to her.

If you go on BBC Bitesize, you can work through chapters which are very accessible, with animations and diagrams to help you. I'd advise doing that first.

This is a straightforward foundation level GCSE question once you know the rules. The smaller number next to the element symbol, known as the proton number or atomic number, tells you the number of protons.

The number of electrons is always equal to the number of protons in an atom (unless it is an ion - which means it has a positive or negative charge overall).

The number of neutrons is found by taking the smallest number (atomic number) away from the largest number (atomic mass).

Hope that makes sense, but look through BBC Bitesize for a nice, clear and simple explanation.