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Year 9 > Chemistry topic 1 > Flashcards

Chemistry topic 1 Flashcards

1
Q

What is an element

A

a pure substance made up of only one type of atom

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2
Q

What is a compound

A

2 or more elements chemically joined together

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3
Q

What is a mixture

A

2 or more elements or compounds that are not chemically joined together

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4
Q

What is a molecule

A

a group of atoms bonded together

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5
Q

State the chemical symbols-
Oxygen
Hydrogen
Helium
Calcium
Copper
Carbon
Iron
Potassium
Nitrogen
Sodium

A

O
H
He
Ca
Cu
C
Fe
K
N
Na

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6
Q

How are atoms formed?

A

They consist of a positively charged nucleus, containing protons and neutrons, surrounded by negatively charged electrons

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7
Q

What is a nucleus

A

dense, positively charged central part of an atom

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8
Q

What is the mass number

A

the total number of protons and neutrons found ON TOP of the symbol

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9
Q

what is the atomic number

A

the number of protons (which is equal to the number of electrons) found UNDER the symbol

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10
Q

what is standard form

A

shortened way of writing down very small or very big numbers. Formula-
a*10^n where a is always larger than 1 and smaller than 10

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11
Q

What is configuration

A

the arrangement of electrons in an atom

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12
Q

what does the group number tell you

A

how many electrons are in the outer shell of the atom. Elements in groups have similar chemical properties

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13
Q

How do you calculate the configuration

A

Find the atomic number which is the number of electrons. You are allowed 2 electrons in the 1st shell and 8 in the rest

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14
Q

What are ions

A

when atoms lose or gain electrons to achieve a full outer shell. They become stable but are no longer electrically neutral. Metal atoms lose electrons to form positive ions and non metal atoms gain electrons to form negative ions

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15
Q

why are atoms electrically neutral

A

Atoms are electrically neutral because they have equal numbers of protons (positively charged) and electrons (negatively charged).

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16
Q

What is a light microscope

A

light shines up through a specimen and through lenses where it bends to make an enlarged image

17
Q

What are electron microscopes

A

they have greater magnification and resolution than light microscopes

18
Q

why is a stain used

A

to make the organelles within a cell appear clearer

19
Q

What is the resolution

A

the shortest distance between 2 points that can be seen as separate points

20
Q

What are isotopes

A

atoms of the same element with different numbers of neutrons (different mass numbers)

21
Q

what is relative atomic mass

A

the average value that takes account of the abundance of the isotopes of the element/average mass off all the isotopes that make up an element
formula-
(mass no. * abundance (%/100)) + (mass no. * abundance(%/100))

22
Q

how are elements arranged in the periodic table

A

in groups and periods. Elements are arranged in order of increasing atomic number. elements with similar properties are in the same group

23
Q

who created the periodic table

A

Mendeleev

24
Q

what is stable?

A

an electronic configuration that has a full outer shell of electrons

25
Q

What are the noble gases

A

-elements in group 0
-they have stable electronic configurations which means they are unreactive and do not easily form molecules
-inert (unreactive)
-the melting point increases as you move down the noble gases because the atoms get larger and more energy is needed to overcome these forces

26
Q

what does inert mean

A

unreactive

27
Q

what are the alkali metals

A

-elements in group 1
-1 electron in outer shell
-very reactive
-get more reactive as you move down the group because the outer electron is further away from the nucleus
-soft, shiny, low melting and boiling points

28
Q

What are the halogens

A

-group 7
-similar chemical properties
-non-metals
-consist of diatomic molecules (2 atoms)
-as you move down the group the boilng and melting points increase because the molecules become larger and the forces between the, become stronger
-decrease in reactivity as you go down the group

29
Q

sodium reacts with water

A

orange/yellow flame, fizzing

30
Q

How can you prove that an alkaline solution is formed when sodium reacts with water?

A

universal indicator purple which is strongly alkaline

30
Q

potassium reacts with water

A

pink flame, moves around surface

31
Q

What numbers are acidic, neutral and alkaline on the pH chart?

A

ACIDIC-3-5
NEUTRAL-6-7
ALKALINE-7-11

32
Q

formula for total magnification

A

magnification of eyepiece lens times magnification of objective lens

Year 9 (6 decks)

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