periodictable

The Periodic Table and properties of matter

Atoms are made of protons neutrons and electrons. Protons and neutrons are found together in the nucleus of an atom. The nucleus is 100,000 times smaller than the entire neutral atom yet contains over 99.9% of the mass.

Model atoms with nuts, or washers and film cans.

The number of protons determines the chemical properties of an atom, element.

Isotopes of an element have the same number of protons but different numbers of neutrons. e.g. hydrogen, deuterium, tritium all have 1 proton and so the chemistry of hydrogen.

Protons and neutrons have just about the same mass and both are more than 2000 times heavier than electrons. The total number of protons plus neutrons gives the number of grams per mole of an isotopically pure element, the atomic mass Carbon 12 for example is 12 grams per mole. (Most elements occur as mixtures of isotopes e.g. Chlorine, CL which is 50% atomic mass 35 and 50% atomic mass 36 the mixture occuring in nature has a mass of 35.5 grams per mole.

Neutral atoms have the same number of protons and electrons, ions have unequal numbers and may be positive or negative. Oppositely charged ions attract. Cl^- and Na⁺

Experiment charged tapes attract.

Protons are positively charged and attract electrons which are negative with an electric force since they are oppositely charged. Electrons fall toward the nucleus all the time but miss, just as the moon is attracted to the earth by gravity but misses because it is constantly moving to the side.

Protons repel protons electrically, but they attract with a force that is 60 times stronger, the strong nuclear force. That is what holds the nucleus together.

Radioactive decay and half-life

Half-life with coins and dice

Solid Liquid Gas Depending on the temperature and pressure atoms or molecules behave as solids liquids or gasses. Atoms in solids and liquids are touching but those in solids are locked into position so a solid keeps its shape. The energy that holds atoms together compared with the kinetic energy of motion due to temperature determines whether atoms will be solid,liquid,or gas.

Float coins in water
Balls in a rat cage
BBs in a jewel case

On atomic mass units is what fraction of the mass of a carbon-12 atom

The atomic nucleus is what sign of charge?

Elements with the same number of neutrons are?

The oxidation number of O in OF2 is

1 L is how many cm^3?

What kind of conductor is solid cold NaCl, liquid Cu, solid Al, gaseous He, diamond

How big is a microsecond? nanosecond? Millisecond?

If you start with 100 atoms that decay with a half life of 1 minute, how many are eft after 2 minutes.

. Mendeleyev developed the periodic law. What was the other thing that he realized during that time?

a) He discovered a new element.

b) He left open spots for the elements that were not discovered at the time of periodic table.

c) He discovered the molecule of hydrogen after the periodic table.

d) None of the above

The total number of protons that are present in the nucleus can be defined as?

a) Mass number

b) Atomic number

c) Avogadro number

d) Nucleons

A polar covalent bond formation takes place due to?

a) Transference of one electron

b) Transference of one or more electrons

c) Sharing of the electron

d) Sharing of one or more electrons

Above which element in the periodic table lie the elements that cannot be formed in the nuclear fusion

process of stars?

a) Iron

b) Zinc

c) Copper

d) Aluminum

The forces of cohesion are greatest in?

a) Solid

b) Gasses

c) Liquids

d) None of the above

11. Heat is transmitted by conduction in the case of

a) Liquids

b) Gases

c) Solids

d) Vacuum

12. _________ is the fastest mode of transmission

a) Conduction

b) Convection

c) Radiation

d) None of these

13. Out of the following, _____ has the greatest thermal conductivity.

a) Copper

b) Wood

c) Glass

d) Mica

Which subshell can fit the most electrons?

a) s

b) p

c) d

d) f

Which of the following states of matter have a definite volume but not a definite shape?

a) solid

b) liquid

c) gas

d) none of the above

Which of the following elements are characterized by being in the state of a solid at room temperature, being

a good conductors of electricity, and malleable?

a) Li

b) Ag

c) Cl

d) a) and b)

Which of the following is the densest?

a) Water

b) Ice

c) Water Vapor

d) They are all water molecules and subsequently have the same density

Which of the following has the greatest mass?

a) Proton

b) Electron

c) Neutron

d) They are all equal

The mass number is determined in which of the following ways?

a) Number of Protons + Number of Electrons

b) Number of Protons + Number of Neutrons

c) Number of Electrons + Number of Neutrons

d) Number of Protons + Number of Electrons + Number of Neutrons

How many neutrons does Iron (Fe) possess?

a) approximately 30

b) approximately 28

c) approximately 32

d) approximately 26

The nucleus is made up of which of the following?

a) Electrons

b) Neutrons

c) Protons

d) B) and C)

A substance that donates protons in water is known as which of the following?

a) A base

b) An acid

c) A proton donor

d) None of the Above

Which of the following are balanced equations?

I. NaOH + HF ! H20 + NaF

II. CH20 + I2 ! CHI0 + HI

III. HCl + MgCl2 ! Cl2 + HMg

a) I and III

b) II and III

c) I and II

d) I, II, and III

A mole equals 6.02*1023. What is the name of this number?

a) Keplerís Number

b) Avogardoís Number

c) Murieís Number

d) None of the Above

If I have .50 moles of CH20H, how many grams of CH2OH do I have?

a) 15.5 grams

b) 62 grams

c) 31 grams

d) None of the Above

How many covalent bonds can a Carbon molecule make?

a) 1

b) 2

c) 3

d) 4

How many half-lives will it take 8.0 grams of a radioactive material to decay to less than 1 gram?

a) 2

b) 1

c) 4

d) 3

Which of the following statements are true of alpha particles?

I. Losing an alpha particle results in the loss of 4 in the mass number

II. Losing an alpha particle increases the atomic number by 1

III. An alpha particle is made up of two protons and two neutrons

a) I

b) II and III

c) I and III

d) I and II

Which of the following statements are false regarding beta particles?

I. Its mass is equal to an electron

II. Its charge is equal to a proton

III. Losing a beta particle increases the atomic number by 1

a) I

b) II

c) III

d) II and III

What will be the end nuclide that is formed when Uranium-92 (with a mass of 238) emits two gamma

particles, then an alpha particle?

a) Uranium-92

b) Neptunium-93

c) Protactinium-91

d) Thorium-90