El choque sucedió ayer.

Because choque is being treated as a specific event: the crash.

In Spanish, articles are used very often, sometimes more often than in English. So El choque sucedió ayer sounds natural for The crash happened yesterday.

If you removed the article and said Choque sucedió ayer, it would sound wrong in normal Spanish.

Here, choque means crash, collision, or impact.

In context, it usually suggests a physical collision, especially with vehicles. In Spain, if you want to talk about a road accident more generally, accidente is also very common.

So:

• choque = collision/crash
• accidente = accident in a broader sense

That means choque can sound a bit more specific than accidente.

All three can express happened, but they are not identical in tone.

• sucedió = happened, somewhat neutral or slightly formal
• ocurrió = happened, also common and often a bit more formal/report-like
• pasó = happened, very common in everyday speech

So these are all possible:

• El choque sucedió ayer
• El choque ocurrió ayer
• El choque pasó ayer

But the third one is usually less natural with choque than the first two. In everyday Spanish, many speakers would more naturally say:

• El choque ocurrió ayer
• El accidente fue ayer
• Hubo un choque ayer

So sucedió is correct, but it can sound a little more formal or narrative.

Because the sentence refers to a completed event at a specific time in the past: ayer.

In Spanish, the preterite is normally used for:

• finished actions
• single events
• events located at a definite point in the past

A crash is usually seen as a completed event, and yesterday gives a clear time reference, so the preterite fits perfectly.

Because the imperfect usually describes:

• ongoing actions in the past
• repeated/habitual actions
• background information

A sentence like El choque sucedía ayer sounds unnatural because a crash is not usually presented as an ongoing background action.

You use the preterite because the event is viewed as one whole completed occurrence:

• El choque sucedió ayer = the crash happened yesterday

Sucedió is the third person singular preterite of suceder.

The subject is el choque, which is singular, so Spanish uses the he/she/it form.

Basic preterite forms of suceder:

• yo sucedí
• tú sucediste
• él/ella/usted sucedió
• nosotros sucedimos
• vosotros sucedisteis
• ellos/ellas/ustedes sucedieron

So in this sentence:

• subject = el choque
• verb form = sucedió

The accent mark shows where the stress goes: su-ce-diÓ.

Without the written accent, Spanish stress rules would make you stress the wrong syllable. Since the word ends in a vowel, it would normally be stressed on the second-to-last syllable, but here the stress must fall on the last one.

So the accent is needed to mark the correct pronunciation.

Yes. Spanish word order is more flexible than English word order.

The most neutral version is:

• El choque sucedió ayer

But you can also say:

• Ayer sucedió el choque

That version puts more focus on yesterday.

A version like Ayer el choque sucedió is grammatically possible, but it sounds less natural in most everyday contexts.

So for a learner, the safest choices are:

• El choque sucedió ayer
• Ayer sucedió el choque

Yes, that is very natural.

Time expressions such as ayer, hoy, mañana, anoche, and so on can often go at the beginning or the end of the sentence.

Compare:

• El choque sucedió ayer = neutral, very natural
• Ayer sucedió el choque = also natural, with more emphasis on time

So ayer at the end is a completely normal placement.

Yes, it is correct and understandable in Spain.

That said, depending on context, many speakers in Spain might more naturally say something like:

• El choque ocurrió ayer
• Hubo un choque ayer
• El accidente fue ayer

So El choque sucedió ayer is fine, but it may sound a little more written, formal, or narrative than the most everyday spoken option.