|Berkeley—Albert Ghiorso, Bernard G. Harvey, Gregory R. Choppin, Stanley Gerald Thompson, Glenn T. Seaborg elements
Bombard a thin foil of einsteinium with alpha particles in a cylclotron. Newly created mendelevium atoms get knocked out of the foil.
Atomic number 101
Bombard einsteinium-253 with alpha,n particles. Bombard einsteinium-253 with alpha,2n particles. Bombard californium-252 with boron,alpha2n. Bombard einsteinium-253 with alpha,3n particles. Bombard einsteinium-255 with alpha,n particles. Bombard americium-241 with carbon-12,5n. Bombard americium-241 with carbon-12,4n. Bombard americium-243 with carbon-12,5n. Bombard americium-243 with carbon-12,4n. Bombard americium-243 with carbon-13,4n. Bombard americium-243 with carbon-13,3n. Bombard curium-248 with oxygen-18,alpha3n. Bombard ensteinium-254 with oxygen-18. Bombard bismuth-209 with argon-40,4n. Bombard bismuth-209 with argon-40,3n. Bombard bismuth-209 with argon-40,2n.
No stable isotope, all radioactive and plenty of ways to make them but no use except in basic research