What is the half-time of radiocarbon? (carbon-14)

Ar­mor-pierc­ing. The density of gold is 19,320 kg/m3, which is higher than of uranium (18,800) and much higher than of lead (11,340). The ar­mor-pierc­ing ammo is made of uranium for its high density - golden bullets would work for this purpose even better.

Polonium 210. 210Po is ex­treme­ly toxic, with one mi­cro­gram being enough to kill the average adult (250,000 times more toxic than hydrogen cyanide by weight).210Po was used to kill Russian dis­si­dent and ex-FSB officer Alexan­der V. Litvi­nenko in 2006,

Osmium. The density of osmium is 22,570 kg/m3, slightly more than Iridium (22,420) and platinum (21,450). Commonly used metals are con­sid­er­ably less dense - the density of iron is 7,870, lead 11,340 and mercury 13,456.

Uranus and Neptune. The di­am­e­ters of Uranus and Neptune are re­spec­tive­ly 25 362 km and 24 622 km - the dif­fer­ence is only 2.92%.