For --The word translated as "for" introduces a reason or explanation so "because" and, in questions, "why." "For" is better because another common word is also used for "because."

it -- This is from the third-person, singular form of the verb.

is -- The verb "is" here is the common form of "to be" in Greek. It means to have a certain characteristic or remain in a certain condition. It also equates terms or assigns characteristics.  The word also means "to exist" and where it doesn't connect to characteristics or conditions.

easier  -- The word translated as "easier" is a compound word. It means "easy" and "easy work." It is an uncommon word, appearing only seven times in the NT and only five times in the rest of ancient Greek literature. The prefix here means "good" or "better" because the word is comparative. The root word primarily means "beating" or "fatigue". Its root meaning is a "better beating" or "better fatigue."

for -- (IW) This word is not in the Greek source. 

a -- There is no indefinite article in Greek, but when a noun doesn't have a definite article, the indefinite article can be added in English translation.

camel -- "A camel" is translated from a Greek word that means "camel." It is in the form of an object of the verb translated as "to go." However, in Aramaic, a similar word means both "camel" and "rope." In Greek, they are slightly different. There is also the idea that this could be a reference to the "needle" gate in Jerusalem. Read the article here for a pretty good (but not perfect) analysis here.

to -- This "to" is added to create the infinitive form of the following verb.

go -- (CW) "Go" is a word that means "enter," "go or come into" of an accuse "come into court," and has the double meaning of "coming into one's mind." This is not the word usually translated as "go." 

through --  The preposition translated as "through" with the form of object here means "through,"  "over," " "in the midst of," or "by (a cause)." It indicates movement through a place or time, but it also means "by" the sense of "by means of" a given method. -- --  The preposition translated as "for...reason" means with the accusative used here, means "thanks to," "because of,"  "by reasons of," and "for the sake of."

a -- There is no indefinite article in Greek, but when a noun doesn't have a definite article, the indefinite article can be added in English translation.

needle's  -- "Needle" is translated from a Greek word that means "needle."

eye,  - "Eye" is translated from a Greek word that generally means a "hole" or "opening."

than  -- "Than" is translated from a Greek word that means primarily "or" but serves as "than" in a comparison. The same word could also be the exclamation "hi" or the adverb meaning "in truth."

for -- (IW) This word is not in the Greek source. 

a -- There is no indefinite article in Greek, but when a noun doesn't have a definite article, the indefinite article can be added in English translation.

rich - "Rich man" is from an adjective that means "rich," and "opulent." It very much has the sense of ostentatiously rich. Here, it is used with an article, "the rich" but unlike English the sense is not a group of people, which would be plural, not singular, but "one who is wealthy."

man  -- (IW) This word is not in the Greek source. 

to -- This "to" is added to create the infinitive form of the following verb.

enter  -- "Enter" is a word that means "enter," "go or come into" of an accuse "come into court," and has the double meaning of "coming into one's mind."

into -- The word translated as "to" means "into" a place, "towards" as a direction, "in" (a position),  "as much as (of measure or limit)," "in regards to" a subject, "up to" limits in measures, "until" in reference to time, "within" a time limit, and "for" a purpose or object. Used with the Greek "from" it means "from...to."

the -- The word translated as "the" is the Greek definite article, "the," which usually precedes a noun or changes the word it precedes (adjective, infinitive, participle, etc.) to act like a noun. The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those") than the English "the." See this article for more. 

kingdom -- The word translated as "kingdom" can be the region, the reign, the castle or the authority of a ruler. Christ does not seem to use it to mean a physical region, so its translation as "reign" or "realm" seems more appropriate. This is especially true because the "reign" of a king means the execution of his will.

of -- This word "of"  comes from the possessive form (genitive case) of the following word that requires the addition of a preposition in English.  The most common is the "of" of possession.

missing "the/this"  -- (MW) The untranslated word is the Greek definite article," the," which usually precedes a noun or changes the word it precedes (adjective, infinitive, participle, etc.) to act like a noun. The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," and "those"). See this article for more. 

God. -- The word translated as "God" means "God" and "deity." When used by Jesus and in the Septuagint to mean "God, it is introduced with an article, so "the God," "the Divine" or "the divine one." The definite article identifies it as specific.  When a definite article does not introduce it, it refers more generally to "divinity," the nature of God.