Although the concept that things are made of small particles is quite old. The first person who gave the idea of the smallest particle was Democritus in 460 BC. He says cut anything until get very small that you cannot cut more. That he called “atomos” In Greek “a” means “Not” and “tomos” means “Cut” i.e indivisible that you cannot cut more. But the concept that things are made of particles so small that they are invisible from us is not very old. In 1897 J.J.Thomson discovered electron then in 1911 Ernest Rutherford presented the idea of nucleus & electron and after that Neils Bohr gave the model of the atom with a nucleus inside and electron in different orbits. And in 1970 we found that proton and neutron are also not basic fundamental particles but made up of quarks. But whatever latest theories we take like Quantum field theory or The String theory one thing is common that everything we see is composed of things that we cannot see.
But Bible almost 2000 years back has mentioned this fact as in Hebrews 11:3
Hebrews 11:3: By faith we understand that the universe was formed at God’s command, so that what is seen was not made out of what was visible. NIV
Bible here mentioned modern scientific concepts not known before to past generations. Furthermore, as we know that inside nucleus, the particle protons have a similar charge, but instead of repelling each other they keep themselves inside the nucleus. We have theories now that says that they held together by the strong force that binds them and the Neutrons. But see this fact was also mentioned in Bible as in Colossians 1:16-17
Colossians 1:16-17: For by Him all things were created, both in the heavens and on earth, visible and invisible…….and in Him, all things hold together. NASB