Chlorine, with the atomic number 17 has one less proton than argon, with the atomic number 18. The atomic number is the number of protons.
Thallium (Tl) has one more proton then mercury (Hg), mercury has 79 protons, Thallium has 80 protons.
Boron.
Platinum
Tritium, also know as hydrogen 3, has 2 neutrons and one proton
A hydrogen atom, H, is a proton (as nucleus) with one electron orbitting around it. A proton is just (the same as above) one proton, which lacks the electron: H+ .
Thallium (Tl) has one more proton then mercury (Hg), mercury has 79 protons, Thallium has 80 protons.
Be is in the s block too. Li has one less proton than Be.
maybe proton
potasium
Yttrium
A proton has slightly less mass than a neutron.
k
The radioactive isotope for Argon is Argon 40. It is also differs from Potassium 40 by 1 proton. Its one proton above Potassium 40.
Actually every proton has different size in different nucleus. But in general, Proton, 1x10-15 m or "a diameter of approximately one-millionth of a nanometer". The electron, the diameter is less than 1x10-18 m. Likewise, The diameter of an electron is less than 1/1000 the diameter of a proton.
The modern periodic table is sorted by ascending atomic number, not mass number. Argon is heavier but has 18 protons, Potassium has 19. Same deal with Tellurium and Iodine. The table was originally laid in increasing mass but it was discovered that the properties of the elements varied periodically when they were sorted according to the number of protons.
Boron.
Platinum(Pt) has 78 protons. Gold(Au) has 79 protons