It's do at 11 please help. 5. Be prepared to prove your understanding of atomic shells.

6. Understand the basics of isotopes and ions.

7. Know about the term "valence" and how it is used with regard to the atom.

8. Know the basics of acids and bases.

9. Understand the organization of the elements in the periodic table.

6.)Isotopy is a phenomenon whereby atoms of an element exhibit different mass numbers but have the same atomic number. Ion is any atom or group of atoms which possesses an electric charge.

8.) Acid is a substance which produces hydrogen ions (or protons) as the only positive ion when dissolved in water.Base is a substance which will will neutralize an acid to yield a salt and water only.

7.) Valency is the combining power of an element or radical.It is actually the oxidation number assigned to the element or group of elements.

5.) Atomic shells are K,L,M,N.The electrons are negatively charged and revolve around the nucleus in spherical regions called shells or energy levels.

9.) Families of Element:Group 1 &2 make up the s-block.Group 3 to 7 and 0 form the p-block.The transition elements occurs between Groups 2 and 3 in the periodic table.They form the d-block because they contain d electrons in addition to the s and p electron.The lanthanides and actinides also occurs between group 2 and 3 in periods 6 and 7 respectively. They form the f-block because they contain f electrons in addition to the s,p and d electrons.

I hope this helps

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"

the major pests we deal with are insects, weeds and fungal diseases. a pesticide is a product, whether organic or chemical, used to kill the target pest. there are other techniques gardeners should use that can prevent the severe infestations that make the use of pesticides necessary