i. alfabe; unsurlar, esaslar. alphabetical

alfabe = alphabet  [a,b,c,d ......z ]               unsurlar means ---> elements           esaslar = the essentials [in this context because alphabet is first thing to build upon it when you learn a language, it is essential thing in the language ]

s. alfabe sırasına göre.-----> alphabetically [ when you put things order, sometimes we put things in alphabetic order ,for example ;      amasya

                                                                 ankara

                                                                 antalya

                                                                 artvin

                                                                 balıkesir

so "alfabe sırasına göre " literally " according to order of alphabet " which is "alphabetic order " or " alphabetically "

z. alfabe sırası ile ---> literally " with alphabetic order " which is same above.

   Yes it is two words ;

 alfabe ---> alphabet

abece ----> A,B,C   when you read first three letters you get " a + be + ce 

                       its like in english you say  ABC´s  . You use ABC´s when you refer essencials of something. For example ; ABC´s of salvation --> Kurtuluşun ABC ´si.