What kind of change is rusting of iron and what kind ofchange is conversion of a compound into its elements?

a)Both are chemical changes

b) both are physical change

c)rusting of iron is physical change and conversion of acompound into its element is a chemical change.

-The scattering of a - particles b thin metal foilsestablished that

a)electrons are fundamental particles of all mater

b)the mass of an atomis concentrated in a positively chargednucleus

c)atoms are electrically neutral

-Which of the following conclusions can be drawn from JJThomsons cathode ray experiment?

a)atoms contain protons, neutrons and electrons

b)practically all the mass of an atom is

c)atoms contain electrons

- Give an isotope of 12^C

a) 12^C 7

b) 13^C 7

c) 13^C 6

- Write the complete chemical symbol of the isotope ofchlorine whose atoms have 20 neutrons.

a) 37^Cl 17

b) 37^Cl 18

c) 36^ Cl 18

- Identify the group number in the periodic table of X,a representative element, in the ionic compound, XCl3

a) 2

b)3

c) 4-

Represent the most stable ion of oxygen

a) O 2+

b)O 6-

c) O2

- An element's most stable ion formsan ionic compoundwith oxygens, having the formula MO. If the ion of element M has amass number of 25 and 10 electrons, what is the identity of theelement, and how many neutrons does it have?

a) The element is magnesium and it has 12 neutrons

b)The element is magnesium and has 25 neutrons

c) Magnesium and has 13 neutrons

- Give the formula of ionic compound

a) Potassium bromate

b)Sodium hypochlorite

- Name the formulas of the compounds

a)BaN2

b)kBr3

c)AlO2

d)MCl