chapter 4 the periodic table

Question 1

element =

Answer 1

is a substance that cannot be split into simpler substances by chemical means

Question 2

Triad =

Answer 2

group of 3 elements with similar chemical properties in which the atomic weight of the middle one is the approx. the average of the other two

Question 3

Robert Boyle (his invention + explanation)

Answer 3

Boyle’s Law = volume is inversely proportional to pressure at constant temperature

Question 4

Anton Lavoisier (his invention + explanation)

Answer 4

Law of conservation of mass = matter is neither created or destroyed only converted from one form to another

Question 5

Humphrey Davy (his invention )

Answer 5

discovered new elements Na ,k , Ca using electrolysis

Question 6

John Dalton (his invention + explanation)

Answer 6

Atomic theory = element made up of tiny particles - all particles of an element are identical - compounds are chemical combinations of these particles

Question 7

Johann Dobereiner (his invention + explanation)

Answer 7

Triads = groups of 3 elements with similar properties , middle one intermediate in properties Eg: Lithium, sodium ,potassium

Question 8

John New-lands (his invention + explanation)

Answer 8

Law of octaves = properties repeat every 8th element

Question 9

Dmitri Mendeleev (his invention + explanation)

Answer 9

Periodic table = arranged elements by property of space rather than weight , left gaps and predicted properties of elements to go in the gaps eg. Scandium

Question 10

Henry Moseley (his invention + explanation)

Answer 10

Atomic no. = the no. of protons in an atom

Question 11

Modern Periodic law =

Answer 11

when elements are arranged in order of increasing atomic no. the properties of the elements reoccur periodically

Question 12

Mass no. =

Answer 12

sum of the protons and the neutrons in the nucleus of an atom

Question 13

Isotopes =

Answer 13

Atoms of the same element which have different mas no. due to the diff. no. of neutrons in the nucleus Eg. Carbon-12 carbon-13 and Carbon-14

Question 14

Relative Atomic mass = (4)

Answer 14

the average of the mass no. of the isotopes of the element , as they occur naturally , taking their abundances into account, expressed on a scale in which the atoms of the carbon-12 isotope have a mass of exactly 12 units

Question 15

Relative Atomic mass (equation )

Answer 15

mass of one atom of an element /

1/12 mass of one atom of carbon-12

Question 16

5 processes that occur in a mass spectrometer and why

Answer 16

1= vaporization - vacuum quickly turns liquids into gases
2= Ionization - electron gun turns the atoms into ions (positive)
3= Acceleration - negative plates attract the pos. ions accelerating them 
4= Separation in a magnetic field - electromagnet separates the ions according to mass 
5= detection - ions fall on detector and recorded as peaks

Question 17

Principal of mass spectrometry

Answer 17

charged particles moving in a magnetic field are deflected to different extents according to their masses are thus separated according to their masses

Question 18

Aufbau Principal =

Answer 18

When building up the electron config. of an atom in its ground state the electrons occupy the lowest energy levels available

Question 19

The 2 odd d block config. (full)

Answer 19

Cr = 1s2, 2s2 2p6 3s2 3p6 4s1 3d5 Cu = 1s1 2s2 2p6 3s2 3p6 4s1 3d10

Question 20

Hund’s rule of maximum multiplicity (bus fill rule )

Answer 20

when 2 or more orbitals of equal energy are available the electrons occupy them singly before filling them in pairs

Question 21

Pauli exclusion Principal

Answer 21

states that no more than 2 electrons can occupy an orbital and they must have an opposite spin

Question 22

electron config.

Answer 22

shows the arrangement of electrons in an atom of an element.