I'm newbie and sorry for stupid question, I exported private keys from electrum, I was wondering why there is 26 of addresses and private keys, I thought it would be one.
Electrum uses hiearchial determistic(HD) seeds to generate addresses. Using the seed, the client can generate a master private key which can generate a practically unlimited number of addresses. The default behavior of Electrum is to generate addresses till they find an àddress with Bitcoins and generate an additional 10 addresses after that point. Judging by that, you likely had 16 transactions using your wallet.
Close, but not quite... The default gap limit in Electrum is 20 for receive addresses... and 5 for change addresses.
On initial wallet creation, Electrum generates your 1st receive address, and then searches for the next 20 consecutive unused receive addresses looking for coins/transactions before stopping. It then looks for the first 5 consecutive unused "change" addresses for coins/transactions before stopping.
So you have 1 + 20 + 5 = 26 addresses... with 26 private keys