Is helium a noble gas? Is neon a noble gas?

What diagram shows the ionic compound of magnesium oxide

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line

Read the chemical equation. 2c2h2 + 5o2 → 4co2 + 2h2o which of the following statements would be correct if one mole of c2h2 was used in this reaction? one mole of oxygen was used in this reaction. five moles of oxygen were used in this reaction. four moles of carbon dioxide were produced from this reaction. two moles of carbon dioxide were produced from this reaction.