What is the meaning of isotopes?

The proton number of atom R is 14 and its relative atomic mass is 28. Which statement is correct?

What are the reactants in this equation?

Cu(OH)₂ + 2HNO₃ → Cu(NO₃)_{2 +} 2H₂O

Element M and element L are located in Group 1 and Group 17 respectively. Element M react with element L to form a compund.

Element J and element Q have proton number of 12 and 9 respectively.

What is the relative formula mass(RAM) of a compound formed between J and Q?

(RAM: J=24; Q=19)

An oxide of element X has the empirical formula of X₂O. 2.24 g of element X reacts completely with 0.96 g of oxygen. What is the relative atomic mass(RAM) of X?

(RAM: O=16)

Equation: 2H₂O₂ →> 2H₂o + O₂

What is the volume of O₂ produced from the decomposition of 500cm³ of 2 mol dm^-3 hydrogen peroxide at standard temperature and pressure(STP)?

(Molar volume of gas at STP = 22.4 dm^-3 mol^-1 )

Metal X has the following properties.

-Less reactive than iron

-Does not react with iron(II) oxide

Which metal oxide can react with X?

Which statement explains why the reactivity of Group 1 elements when going down the group?

Some transition elements and their compounds are useful catalysts in industry. Which pair is correct?