I have exactly the same laptop and had exactly the same issue.
The solution? Install BudgieOS on it first. This is a distribution based on Ubuntu 16.04.
This distribution has (for some reason) different or additional drivers which enable the WiFi on this laptop. Make sure you install the 3rd party drivers.
After you have installed it, you may quite like the look - it's quite different from the default Ubuntu, but I quite like it.
If you would rather the default Ubuntu look, after booting it open the Terminal by clicking the circle in the top, then Utilities then Terminal, or with the keyboard shortcut Ctrl + Alt + T.
You will need to be connected to the WiFi for this, but, hopefully, you will be (yay) - so there's no issue there!
Into the terminal, type this:
sudo apt-get update
and press enter. Wait for the command to finish - it's finished when the text stops scrolling and the terminal has
user@computer-name:~$ at the bottom. then type this:
sudo apt-get install ubuntu-desktop
and press enter again.
This will install the Unity desktop with the default Ubuntu look. Restart the computer, and at the login screen
Wait for the command to finish (you may have to press Enter to confirm). It will take a while. Partway through the installation for me, I was logged out. I had to run these commands in the Terminal after I logged back in - but you only need to do this if you are logged out too!
sudo rm /var/lib/apt/lists/lock
sudo rm /var/cache/apt/archives/lock
Now log out. Click in the top right corner, and click the lower right power button, and choose log out.
You will see this:
In the top bar, click the left most icon - a circle with a leaf shape in it: and select Ubuntu. The icon will change, and then you log in again.
This is almost the standard Ubuntu desktop - just a couple of final tweaks to make. Click the settings icon in the sidebar and select Appearance. Then, next to the Theme label, select "Ambiance" from the dropdown.
Now click the Ubuntu icon in the upper left. Search for "Startup" and select the first result - "Startup Applications". Deselect
Enjoy your Ubuntu installation with working WiFi!