The previous page is sending you to https://www.yaklass.ru/p/himija/11-klass/osnovnye-poniatiia-i-zakony-khimii-6931691/zakonomernosti-izmeneniia-svoistv-elementov-i-ikh-soedinenii-po-perioda_-6957324/re-85be6ef3-82c9-414e-b19b-87eee9f0c47f.

 If you do not want to visit that page, you can return to the previous page.