Chemistry And Physics Gr.10 June

Question 1

What is a pulse?

Answer 1

A single disturbance through a medium.

Question 2

What is amplitude?

Answer 2

The maximum disturbance of a particle from its rest position.

Question 3

What is a transverse pulse?

Answer 3

A vibration causes particles of a medium to move at right angles to the direction of propagation of the pulse.

Question 4

What is superposition of pulses.

Answer 4

The addition of the disturbances of the two pulses that occupy the same space at the same time.

Question 5

What is constructive interference?

Answer 5

Two crests/ troughs meet and their amplitudes reinforce each other and the total amplitude is the sum of the individual amplitudes.

Question 6

What is destructive interference?

Answer 6

One crest and one trough meet and cancel each other out if they have equal amplitudes.

Question 7

What are transverse waves?

Answer 7

A succession of transverse pulses in the medium travel at right angles to the direction of propagation of the wave.

Question 8

What term describes the motion of particles in a medium when a wave passes them?

Answer 8

The particles oscillate

Question 9

What is a wavelength?

Answer 9

The distance between two consecutive points that are in phase.
Measured in metres.

Question 10

What is a period?

Answer 10

The time it takes for one full cycle.

Measured in seconds.

Question 11

What is a frequency?

Answer 11

The number of vibration cycles per second.

Measured in Hertz.

Question 12

Who discovered that atoms contain protons and electrons?

Answer 12

Thomson

Question 13

Who discovered that electrons move in electron clouds?

Answer 13

Schrödinger

Question 14

Who discovered that elements are made from atoms?

Answer 14

Dalton

Question 15

Who discovered that electrons move around nuclei in orbits and energy levels?

Answer 15

Bohr

Question 16

Who discovered that atoms consist of mostly empty space?

Answer 16

Rutherford

Question 17

What did Schroedinger discover?

Answer 17

Electrons move in electron clouds.

Question 18

What did Dalton discover?

Answer 18

Elements are made from atoms

Atoms of the same element are the same

Atoms can form compounds

Atoms can’t be created/ divided destroyed

Question 19

What did Broglie discover?

Answer 19

Electrons have wave-like properties.

Question 20

What did Thomson discover?

Answer 20

Atoms contain positive and negative particles.

Negative particles are embedded in a positively charged area

Question 21

What did Bohr discover?

Answer 21

Electrons move around the nucleus in orbits/shells and energy levels

Electrons have amounts of energy

Question 22

What did Rutherford discover?

Answer 22

Atoms consist mostly of empty space

Protons exist in the centre of atoms

Electrons around the outside

Question 23

What experiment did Rutherford use to prove that atoms consist mostly of empty space?

Answer 23

The gold foil experiment.

Question 24

Why are electrons not used to calculate atomic mass?

Answer 24

Their mass is so small that it’s NEGLIGIBLE.

Question 25

What is relative atomic mass?

Answer 25

The average mass of all the atoms of that element, taking into account all the isotopes.

Question 26

What is electron configuration?

Answer 26

The way electrons are arranged around the nucleus.

Question 27

What are two states of electrons?

Answer 27

Excited state and ground state

Question 28

What happens when an excited electron falls back to its ground state?

Answer 28

The same energy as what was absorbed is released as light.

Question 29

What are core electrons?

Answer 29

The number of electrons in the inner energy level of an atom.

Question 30

What are the electrons in the last energy level of an atom called?

Answer 30

Valence electrons

Question 31

What are ions?

Answer 31

Charged particles

Question 32

Give another name for group 1 and give its chemical properties.

Answer 32

Alkali metals Low densities, good conductors, alkaline solutions in water, react with water Down group: hardness decreases, mpt decreases, reactivity increases

Question 33

Give another name for group 2 and give its chemical properties.

Answer 33

Alkali earth metals Less reactive than group 1, silvery, alkaline solutions in water, form solid oxides Down group: reactivity increases

Question 34

Give another name for group 17 and give its chemical properties.

Answer 34

Halogens Diatomic, low mpts and bpts Down group: reactivity decreases, mpts/bpts increase

Question 35

Give another name for group 18 and give its chemical properties.

Answer 35

Noble gases Unreactive Down group: bpts decrease

Question 36

What is the name of the middle block of the periodic table?

Answer 36

Transition metals

Question 37

Give another name for groups 1 and 2

Answer 37

The s-block

Question 38

Give another name for groups 13-18

Answer 38

The p-block

Question 39

What is valency?

Answer 39

The number of electrons that an atom must gain, lose or share to achieve the stability of a noble gas.

Question 40

What is density?

Answer 40

The type of bonds between the atoms of an element determines the density of an element at room temperature.

Question 41

What pattern does the periodic table show for density?

Answer 41

Density increases down a group

Question 42

What pattern does the periodic table show for mpts and bpts?

Answer 42

For metals: increases across periods For non-metals: decreases across periods C and Si have very high mpts and bpts

Question 43

What is an atomic radius?

Answer 43

The distance between the nucleus and the last orbital

Question 44

What pattern does the periodic table show for atomic radius?

Answer 44

Increases down group Decreases across period

Question 45

What is ionisation energy?

Answer 45

The amount of energy required to remove an electron from a neutral atom.

Question 46

Which group has the highest ionisation energy?

Answer 46

Noble gases

Question 47

What pattern does the periodic table show for ionisation energy?

Answer 47

Increases across period Decreases down a group

Question 48

What is electron affinity?

Answer 48

The ability of an atom to accept one or more electrons. (Know but not part of def.: Metals lose electrons and non-metals gain electrons when they react)

Question 49

What pattern does the periodic table show for electron affinity?

Answer 49

Increases across a period

Question 50

What is electronegativity?

Answer 50

The tendency of an atom to attract electrons towards itself and form a negative ion.

Question 51

What pattern does the periodic table show for electronegativity?

Answer 51

Increases across a period Decreases down a group

Question 52

What are the colours of the following elements? Fluorine Chlorine Bromine Iodine

Answer 52

Fluorine. Yellowish Chlorine Greenish Bromine. Brown-orange Iodine Purplish

Question 53

What is ionic bonding?

Answer 53

When one or more electrons are transferred from a metal atom to a non-metal atom.

Question 54

What do you call a: Metal that forms an ion? Non-metal that forms an ion?

Answer 54

Metal that forms an ion: cation Non-metal that forms an ion: anion

Question 55

What do you call the structure that ions are packed into?

Answer 55

A crystal lattice

Question 56

What holds ions together?

Answer 56

Electrostatic forces

Question 57

Why do ions have high melting points?

Answer 57

Their electrostatic forces are very strong. It takes a lot of energy to overcome these forces.

Question 58

What is metallic bonding? | Maybe double check def. by looking in text book

Answer 58

The chemical bond between atoms of the same element.

Question 59

In metallic bonding, what surrounds the positive atomic nuclei (kernels)?

Answer 59

A sea of delocalised electrons

Question 60

What is the difference between relative molecular mass and relative formula mass?

Answer 60

Relative molecular mass-molecular compound Relative formula mass-ionic compound

Question 61

What is wave speed?

Answer 61

The distance a wave travels in a certain amount of time.