Can some one help? ?

Question

21. Circle true or false for each of the following statements.

a) Ionic compounds form by elements sharing electrons T / F

b) A molecule is a compound with covalent bonds T / F

c) Protons and neutrons have the same mass and charge T / F

d) Electrons and neutrons have the same mass T / F

e) Atomic number is the number of protons in an element T / F

f) Atomic weight is always a whole number T / F

g) A mixture can be separated into its components by physical means T/ F

h) Elements which form negative ions are always not-metals T / F

i) Hydrogen bonding is a weak intermolecular force T / F

22. Depict the structure of an atom using hydrogen and carbon as examples.

Show nucleus, protons, electrons and neutrons as appropriate. (4 marks)

23. Indicate whether the following are ionic or covalent compounds and explain why.

a) H2O

b) Na2O

c) CCI4

d) MgCI2

Answer 1

21.

a) false, that's covalent compounds

b) false, not all covalent molecules are compounds. Molecules have covalent bonds but the molecules O2, N2, Cl2 etc are elements, not compounds (compounds have >1 element)

c) false: same mass, but protons are +ve, neutrons are neutral

d) false: neutrons are about 1800x the mass of electrons

e) true: atomic number defines the element and is the number of protons in the nucleus

f) false: isotopes change virtually all atomic weights away from whole numbers

g) true

h) true

i) true

22.

Hydrogen:  http://physics.gmu.edu/~rms/astro113/ima...

Carbon (6 protons and 6 neutrons in nucleus:

http://physics.uoregon.edu/~courses/Brau...

23.

Look at the electronegativity of each element in the compound.  If the difference between the two is >1.7, it's ionic, if it's <1.7, its covalent

a) e neg H = 2.2, e neg O = 3.4, diff <1.7 so covalent

b) e neg Na = 0.9, e neg O = 3.4, diff >1.7, so ionic

c) e neg C = 2.5, e neg Cl = 3.2, diff <1.7, so covalent

d) e neg Mg = 1.3, e neg Cl = 3.2, diff >1.7, so ionic

Answer 2

o my ..

a. f

b. t

c. t

d. f

e. f

f. f

g. t

h. t

i. f

22.           you need to draw this out.. lilke this >>http://images.google.com/imgres?imgurl=h...

a. no........ forget

b. yes.        ..........forget  

c. yes. .........foget

d. no ........forget

Answer 3

a) Ionic compounds form by elements sharing electrons T / F -F

b) A molecule is a compound with covalent bonds T / F - T

c) Protons and neutrons have the same mass and charge T / F -F

d) Electrons and neutrons have the same mass T / F -F

e) Atomic number is the number of protons in an element T / F- F

f) Atomic weight is always a whole number T / F -F

g) A mixture can be separated into its components by physical means T/ F - T

h) Elements which form negative ions are always not-metals T / F - T

i) Hydrogen bonding is a weak intermolecular force T / F - T