Elements questions This is a list of recently added questions about elements. How many hydrogen isotopes occur naturally on the Earth?Three isotopes of hydrogen occur naturally on the Earth: the most frequent protium (1H), deuterium (2H) and tritium (3H). Other isotopes of hydrogen (4H-7H) were created in laboratories and are highly unstable.Created by: Paweł Kołodziejczykhard 57% oneone2081twotwo3226threethree8524fourfour893names riddles » Which of the following countries doesn't have its "own" element?Italy. Polonium was discovered by Maria Skłodowska-Curie in 1898 and named in honour of Poland. Germanium was named by the German chemist Clemens Winkler. Francium was named by the French chemist and the physicist Marguerite Perey. Created by: Paweł Kołodziejczykeasy 70% PolandPoland554GermanyGermany816ItalyItaly5067FranceFrance783chemistry riddles » Which chemical element has been named after the Sun?Helium was first discovered in 1868 as the unexpected line in the spectrum of the chromosphere of the Sun - and so it was named after the Greek word Helios (Sun).Created by: Shankar Kumaraverage 69% GoldGold2732HeliumHelium8994OxygenOxygen257PhosphorusPhosphorus1036Sun riddles » What makes depleted uranium a good material for making ammunition?High density. Depleted uranium is 1.67 times as dense as lead, 84% as dense as osmium or iridium, which are the densest known substances under standard (i.e., Earth-surface) pressures. Consequently a depleted uranium projectile of given mass has a smaller diameter than an equivalent lead projectile, with less aerodynamic drag and deeper (armor-piercing) penetration due to a higher pressure at point of impact.Created by: globalquiz.orghard 44% radioactivityradioactivity1684high densityhigh density7965explosivenessexplosiveness3615extreme hardnessextreme hardness4818firearms riddles » This is an iron buoy. Where were its atoms formed?In a high-mass star preceding Sun. Radioactive nickel-56 (which decays to the most common isotope of iron) is the last element to be produced before the collapse of a supernova. That is why the iron was abundantly scattered into space after the supernova explosion.Created by: life-o-holicvery hard 34% in a high-mass star preceding Sunin a high-mass star preceding Sun4656in the Sunin the Sun1134in the Earth's corein the Earth's core3983in the Earth's crustin the Earth's crust3851physics riddles » What is the most common element (by mass) forming the planet Earth?Iron is most abundant in the Earth's outer and inner core, and it is the fourth most common element in the Earth's crust.Created by: globalquiz.orgvery hard 29% carboncarbon2474oxygenoxygen1793ironiron2496siliconsilicon1761Earth riddles » What was graphite believed to be a form of?Lead. When large deposit of graphite was found in the 16th century in England, it was thought to be a form of lead. In many languages, the word for pencil literally means lead pen. (German Bleistift, Polish ołówek, Arabic قلم رصاص) Created by: Kasiaaverage 64% leadlead15413mercurymercury1792ironiron2721chalkchalk4155writing riddles » Play chemistry quiz and see all the questions.