How do you determine when an adjective is a soft adjective when the ending is not ний

Question

From the limited available resources online, i was able to determine at first that soft adjectives is just with the stem ending ний as explained on these websites (http://masterrussian.com/aa040801a.shtml)(http://www.russianlessons.net/grammar/adjectives.php) but then when i was doing some exercises that required me to conjugate adjectives to different cases i ran into some adjectives that took the soft stem ending instead of the hard adjective ending which i thought it would be. Example: горячий чай (nominative singular case) --> горячему чаю (dative singular case) I don't understand why this would take the soft adjective declensions rather than hard adjective declensions.

Another thing i could not understand the conjugation of: мягкий ковёр --> мягкому ковёр Why would it not be мягкему instead of the correct answer for the declension in the dative case мягкому.

i have been looking at the definition of soft adjectives and why they are formed on https://en.wikibooks.org/wiki/Russian/Grammar/Adjectives and understand that they are formed because of the 7 letter spelling rule, but it still doesn't explain why some adjectives are declined as if they are soft when they don't end in the stem ний. Is it just best to memorize which of the adjectives are soft because i cannot find any information online about this subject.

Answer 1

According to the resource you've provided (https://en.wikibooks.org/wiki/Russian/Grammar/Adjectives).

1) Let's take a look at мягкий ковёр. The ending is NOT -ний, -няя, -нее, then, it does not have soft ending.

The dative form is мягкому ковру. The explanation:

If the adjective ends in the 5-letter rule (ш, щ, ч, ж, ц) or the soft ending (-ний), they end in -ему.

Мягкий does not have soft ending, it also does not end on ш, щ, ч, ж, ц. So the only left conclusion is to add -ому.

2) Now let's take a look at горячий чай. The ending is NOT -ний, -няя, -нее, then, it does not have soft ending.

The dative form is горячему чаю. The explanation:

If the adjective ends in the 5-letter rule (ш, щ, ч, ж, ц) or the soft ending (-ний), they end in -ему.

Горячий does not have soft ending, but it does end on ч. So the only left conclusion is to add -ему.