The most difficult elements riddles A list of elements related questions that are most often answered incorrectly Chemistry quiz 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.very hard 30% carboncarbon27%oxygenoxygen20%ironiron30%siliconsilicon20%Created by: globalquiz.org. Statistics based on 7241 answers in 2 languages »Earth 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.very hard 34% in a high-mass star preceding Sunin a high-mass star preceding Sun34%in the Sunin the Sun8%in the Earth's corein the Earth's core29%in the Earth's crustin the Earth's crust27%Created by: life-o-holic. Statistics based on 11428 answers in 2 languages »physics 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.hard 41% radioactivityradioactivity10%high densityhigh density41%explosivenessexplosiveness21%extreme hardnessextreme hardness27%Created by: globalquiz.org. Statistics based on 13251 answers in 2 languages »firearms riddles » 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.hard 59% oneone13%twotwo20%threethree59%fourfour6%Created by: Paweł Kołodziejczyk. Statistics based on 10070 answers in 4 languages »names 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) average 64% leadlead64%mercurymercury7%ironiron11%chalkchalk16%Created by: Kasia. Statistics based on 20354 answers in 2 languages »writing 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. average 69% PolandPoland7%GermanyGermany11%ItalyItaly69%FranceFrance10%Created by: Paweł Kołodziejczyk. Statistics based on 5629 answers in 2 languages »chemistry 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).easy 70% GoldGold20%HeliumHelium70%OxygenOxygen1%PhosphorusPhosphorus7%Created by: Shankar Kumar. Statistics based on 8392 answers in 4 languages »Sun riddles » Play chemistry quiz and see all the questions.