The IP addresses of most social media networks can be detected while using TCP listening software. However I don't think you want to go through all that trouble, so first off the easiest one would be instagram because it has it's own website. However based on the other services you'd like to block I'm going to make a far out guess you want your kid to stop using those apps.
Complication #1: Those apps will change IPs likely every few updates.
Complication #2: Each country will have different IPs, in fact it may be that many major cities will have their own server and whichever one you happen to be nearest will be connected to first. But if you'd like to find out what they are from your home you can run "traceroute" in a terminal window. This is my output:
traceroute instagram.com
traceroute: Warning: instagram.com has multiple addresses; using 34.207.25.209
traceroute to instagram.com (34.207.25.209), 64 hops max, 52 byte packets
1 192.168.0.1 (192.168.0.1) 2.330 ms 1.987 ms 1.673 ms
ETC
12 54.239.108.129 (54.239.108.129) 788.367 ms
54.239.111.5 (54.239.111.5) 758.657 ms
54.239.108.129 (54.239.108.129) 788.507 ms <br>
13 72.21.222.149 (72.21.222.149) 729.331 ms
205.251.245.181 (205.251.245.181) 708.934 ms
52.93.24.104 (52.93.24.104) 728.756 ms <br>
14 * 205.251.244.69 (205.251.244.69) 781.920 ms
205.251.244.99 (205.251.244.99) 744.076 ms
How I would approach the problem: If you have access to the device, enable a parental lock that prohibits usage of the app. Depending on what type of device you're using e.g. iOS or Android, and their respective device versions, you'll want to look up how to administer it.
If you somehow had the IPs of those services, the best way to block them would be to block it from your router. I have a Hitron Hub router at home offered by Shaw Telecom and it can block IPs for specific devices or globally. Hope I've helped :)