Vi legger sjokkelektrodene på brystkassen.

Because Norwegian usually writes compound nouns as a single word.
Here, sjokkelektrodene is made up of:

• sjokk = shock
• elektrode = electrode
• -ne = the definite plural ending

So sjokkelektrodene means the shock electrodes.

This is very normal in Norwegian. English often uses separate words where Norwegian prefers one compound word.

The ending -ne marks definite plural for many nouns in Norwegian.

So:

• en elektrode = an electrode
• elektroder = electrodes
• elektrodene = the electrodes

In this sentence, sjokkelektrodene is definite plural: the shock electrodes.

Legger is the present tense of å legge, which often means to lay, to put, or to place.

So:

• å legge = to place / to put down
• legger = place / are placing / put

In this sentence, legger sounds natural because the electrodes are being physically placed onto the body.

Norwegian often uses å legge when something is placed lying against a surface or put down onto something.

That fits electrodes well: they are being placed onto the chest.

Å sette is more often used for putting something upright, into position, or into place in a different way.
So vi legger sjokkelektrodene på brystkassen sounds more natural in this context.

På usually means on or onto.

Here it is used because the electrodes are placed on the surface of the chest. That matches the physical idea very well.

So på brystkassen means they are attached or placed on that area of the body, not inside it or next to it.

Brystkassen is a definite singular noun.

It is built from:

• bryst = chest
• kasse = box
• -en / here appearing as -n in the final form = the definite ending

So brystkassen literally looks like the chest box, but in real usage it means the chest or the rib cage/chest area.

Body parts are often expressed with definite forms in Norwegian.

In Norwegian, body parts are very often used in the definite form, especially when referring to a specific part of someone’s body in a real situation.

So Norwegian commonly says things like:

• i hånden = in the hand
• på hodet = on the head
• på brystkassen = on the chest

This can sound a bit different from English, but it is very natural in Norwegian.

No, this is standard Norwegian main-clause word order:

• Vi = subject
• legger = verb
• sjokkelektrodene = object
• på brystkassen = prepositional phrase

So the structure is:

Subject + verb + object + place

That is very straightforward and similar to English in this sentence.

A useful breakdown is:

• vi = we
• å legge = to place / to lay
• sjokkelektrodene = the shock electrodes
• på brystkassen = on the chest

So the verb’s dictionary form is å legge, while legger is the present-tense form used in the sentence.

More or less, yes. The beginning sj- in Norwegian is pronounced like the sh sound in English.

So sjokk sounds close to English shock.

Also:

• sjokk-elektrodene is easier to understand if you mentally separate the compound into parts.
• Norwegian compounds are often easier to read once you learn to spot the smaller words inside them.

Yes, you often could, depending on context.

• brystet = the chest
• brystkassen = the chest / rib cage area, often a bit more anatomical or clinical

In a medical context, brystkassen can sound slightly more precise.
Brystet is also common and natural, but it may feel a little less technical.