Naming alkenes- geometric isomers

Alkanes were pretty straightforward, but now I’m naming them Alkenes, and it’s become a lot more confusing.
I am now presented with side groups using their chemical name instead of the long chain, but I've not been shown how to draw or identify this.
I'm familiar with ch₃ being methane, but I don't know what ch₂ is, especially when they're combined ch₃ch₂.
I have taken the illustration given and tried to draw it in a way I understand to identify the long chain best.
I understand, based on the location of the two halos or alkyl groups connected to the double bond, that you use either trans or cis.
From what I have derived, the name is as shown in my attachment.
But I could be wrong.


So, they have methyl located on the third carbon which makes me believe my drawing is wrong

Your drawing of the elements and bonds is correct but start counting the carbons from the other end, the carbon you have as 6 in your drawing should be labelled carbon 1. This is because as a rule you want to use the smallest numbers possible for substituent groups (in this case the methyl group) so by counting this way around it’s trans-3-methyl… As a side note, CH3CH2 is an ethyl group just as CH3 is a methyl group, and CH3CH2CH2 is a propyl group etc. Hope this makes sense

Sorry, this email went into my junk box so I figured no one knew the answer lol.
I see what you’re saying by counting the other end because I have five h bonds, where as the other side I have 6 bonds.
I learned that ch3 by its self is a methyl group.
So, CH3CH2 is an ethyl group. When presented this way, I just consider combining them, so, C₂H₅ which we know as ethane and same with propyl group, C₃H₇ being propane. So, why can’t they just state that lol

C2H5 (or CH3CH2) is an ethyl group which is different to ethane (C2H6) which has one additional hydrogen, same with a propyl group and propane. Ethyl groups (and other alkyl groups) are substituent groups in a molecule just like the methyl group in the example above, whereas ethane is a molecule itself.