Chemistry Midterm Garbage

When ionic bonds are formed, metallic atoms tend to

lose electrons and become positive ions

When energy is absorbed, the excited electron

moves into a higher energy level. The more energy absorbed, the higher energy level is attained by the electron. Ex. Which principal energy level change by the electron of a hydrogen atom will cause the greatest amount of energy to be absorbed? 1. n = 2 to n = 4 2. n = 2 to n = 5 3. n = 4 to n = 2 4. n = 5 to n = 2 The answer is 2, although 1 does have an electron moving to a higher energy level, the electron moves more in choice 2 making it the correct answer.

The mass of an atom is made primarily of

neutrons and protons

High electronegativity =

stronger attraction for electrons, lower electronegativity = less attraction for electrons

To find the number for neutrons

subtract the atomic # from them atomic mass

Atomic radius

tends to decrease as you go across each period

Group 1 of the periodic table is also known as

the alkali metal group ((EXCLUDING HYDROGEN))

Electrolysis is

decomposition reaction involving water and producing H+ and OH− ions

_+_+_+_+_+_+_+_+_+_+_+_+_+_+_ (positive) ------------------------------------------------^^^^ (1) ------------------------------------------------------------->>>>> (2) -------------------------------------------------vvvv (3) _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_ (negative)

1. beta - high speed electron (0 atomic mass, −1 charge) ; referred to by the symbol β 2. gamma - (γ) are similar to high energy x-rays 3. alpha - helium nucleus (atomic number 2, atomic mass 4), referred to by the symbol alpha

1 mole is equal to

22.4 L 1 GFM 6.02 x 10 ^ 23

Ionic bonds are formed when electrons are transferred from

Metal to Non-metal elements. Ex. NaO

To find mass percentage of an element in a compound you

Find the gram formula mass of the whole thing, then the gfm of the single element you are trying to find. Divide the # of the desired element by the total of the compound, then multiply that number by 100. Ex. What is the percent by mass of Sulfur in Sulfur Dioxide? S- 1 x 32 = 32 O- 2 x 16 = 32 32 + 32 = 64 (64/32) = .5 (100) = 50%

Noble Gases are found in

Group 18

Common radioisotopes

Iodine - 131: Thyroid disorders Technetium- 99 : Locating brain tumors Radium-226 & Cobalt-60: used in cancer therapy Uranium - 238: used for dating rocks.

Isotope

Same atomic #, different atomic mass This is due to the fact that there is different amount of neutrons ((Different version of the same element)) Ex. 12 14 < mass # C C < element 6 6 < atomic # (6 neutrons) (8 neutrons) < amount of neutrons

determining the strength of Ionic bonds

The strength of an ionic bond is measured by difference in electronegativity. The smaller the difference the less ionic the bond is. Ex. H (2.7) F (4.0) - I (2.2) - H (2.7) = 0.5 > ionic than =1.3

Using protons to find an atom

You don't need to! Each atom's atomic # is based off the # of protons it's nucleus contains. Ex. What is the name of an atom with 13 protons & 14 neutrons? Aluminium, atomic # of 13!

The atomic mass of an element is

a weighted average. Ex. If 75.0% of the isotopes of an element have a mass of 35.0 amu and 25.0% of the isotopes have a mass of 37.0 amu, what is the atomic mass of the element? (.75 x 35.0) + (.25 x 37.0) = 35.5 amu

Ions of transition elements tend to be colored in

both solid and in solution

Active non-metals have high

electronegitivity

Moles of atoms in one mole

in order to find the # of moles of atoms in one mole of a compound, you need only to find the number of elements. Ex. What is the total number of moles of atoms in one mole of (NH4)2 SO4? N x 2 = 2 H x 8 = 8 S x 1 = 1 O x 4 = 4 = 15 atoms

As Atomic # increases, electronegativity

increases. They have a direct relationship. http://college.cengage.com/chemistry/intro/zumdahl/intro_chemistry/5e/students/protected/periodictables/pt/pt/pt_e2.html

Ionic radius

is smaller if the atom loses electrons when forming the ion