Why are the lanthanoid elements not found in nature in their elemental forms?

Let the ed50 of a recreational drug be defined as the amount required for 50% of a test group to feel high or get a buzz. if the ed50 value of ethanol is 470 mg/kg body mass, what dose would a 70 kg party goer need to quickly consume in order to have a 50% chance of getting a buzz? 235 mg 470 mg 32,900 mg 35,000,000 mg

What is the compound name for the formula [ru(en)2cl2]2+ and [co(en)cl2br]-

Gasoline has a density of 0.740 g/ml. if you have 328 grams of gasoline, what is the volume in milliliters?