From Wiki:
The Emerging Sources Citation Index is a citation index produced since 2015 by Thomson Reuters, and now by Clarivate Analytics. According to the publisher, the index includes "peer-reviewed publications of regional importance and in emerging scientific fields".[1] It has been observed that among the databases produced by Clarivate Analytics, the Emerging Sources Citation Index is the easiest one to get into and that as a result it contains many predatory journals.

Simply, to compute the impact factor for a journal in a certain year A, say, the following formula is used

                               IF= (C(A-2)+C(A-1))/(N(A-2)+N(A-1))

Where C(X) is the number of citations that journal has received in year X and N(X) is the total number of papers published in that journal in the year X.

For more details, please visit:

https://en.wikipedia.org/wiki/Impact_factor

The following paragraph is taken from: https://www.researchgate.net/post/Scopus_vs_Clarivate_Analytics_journals It is rare for predatory journals to be indexed by lists such Scopus but it does happen. For some examples, see Working Paper Do not feed the predators (or for information on the published version, see Article Do not feed the predators). This being said, it is more common for predatory journals to lie about being indexed by such lists or, as Kay Smarsly says to be indexed by fake indexed factors (for examples of such fake indexed factors, see https://beallslist.weebly.com/misleading-metrics.html).

Yes, this depends on whether the journal applied to the database. For example, as of January 2019, "Journal of Taibah University for Sciences" is listed in Clarivate analytics under "Science citation index expanded" but it is not listed in Scopus.

Yes, provided that the journal is Refereed, scientific and specialized in the reasearcher's topic, as well the journal is listed in Science Citation index or Social Citation index, taking into consideration the available budget and the frequency of publication in the same journal with other alternatives.

Yes, this is based on the principles decided by deans’ council; please visit this link for further information.

http://mjl.clarivate.com/

In the search slot, write the journal name or the ISSN. If the journal is listed, press "coverage" to know the exact classification of the journal.