Electrum has the same master public key that is used in the service you've stated. With that, Electrum will constantly query for transactions in addresses within the gap limit.

For example, your gap limit is 25 addresses. After the initial address generated by default by Electrum, Electrum will continue to look for transactions in the next 25 address. If the next address has a transaction associated with it, Electrum will query another 25 addresses after it, and so on.
Nope.