Neutrons have no net electric charge because they are composed of three elementary particles: two down quarks and one up quark. Quarks are the fundamental building blocks of protons and neutrons, and they carry fractional electric charges.

- The up quark carries a charge of +2/3 e, where "e" represents the elementary charge, which is approximately 1.602 x 10^-19 Coulombs.

- The down quark carries a charge of -1/3 e.

Now, let's look at how these charges combine to form a neutron:

A neutron consists of one up quark and two down quarks. So, the sum of the charges of its constituent quarks is:

(2/3 e) + (-1/3 e) + (-1/3 e) = 0

As you can see, the total charge of the quarks in a neutron adds up to zero. This means that neutrons have no net electric charge.

In contrast, protons are also made up of three quarks (two up quarks and one down quark), but the combination results in a net positive charge. The charges of the up and down quarks in a proton are:

(2/3 e) + (2/3 e) + (-1/3 e) = 1 e

So, protons have a net positive charge of 1 elementary charge (1e), while neutrons have no net charge (0e). This difference in charge is why protons are positively charged, electrons are negatively charged, and neutrons are electrically neutral.

“Why do Neutrons have no charge?”

- neutrons have no charge because of Matter is rather simple informational system that is based on a simple binary reversible logics, and so Matter’s ultimate base is the (at least) [4+4+1]4D dense lattice of primary elementary logical structures – (at least) [4+4+1]4D binary reversible fundamental logical elements [FLE].

Correspondingly at design/creation of Matter to make Matter as it is – i.e. practically infinite diversity of material objects – substances, stars, galaxies, etc., which eventually are made by using only a few stable particles, further ~ hundred nuclei/atoms, in the design some [at least 4 known now] binary logical constructions - “fundamental Nature Gravity, Weak, Electric, and Nuclear, forces” were included, that compose from FLEs everything in Matter;

- however the simple logics has some limitations, so it turned out to be that at composing of atoms, that consist of positively charged nuclei and negatively charged electrons, so in principle, nuclei could contain only positively charged protons,

- because of that Nuclear Force is short rang Force, while Electric Force is long range Force, if in a nucleus would be many protons, this nucleus could not exist because of protons electric repulsion. So in the design electrically neutral neutrons are included, which interact only by Nuclear Force, and so in large nuclei “dilute proton substance” decreasing electric repulsion, what makes nuclei be stable up to [number of protons] Z a bit

An alternative view:

Electric charge is nothing but the relative direction of lines of force of an electric field. Depending on the direction of observation, every electric field has both positive and negative electric charges.

Both electrons and positrons have similar electric fields about them.

Protons and neutrons are similar single-layered spherical shells formed by primary 3D matter particles. The only difference is that a proton contains an additional positron in its shell and the neutron has no positron. Hence, a neutron exhibits no resultant electric field about it while a proton exhibits a resultant electric field about it due to the presence of its constituent positron. See: hppts://www.matterdoc.info