Chemistry 4: Chemical Patterns Flashcards Preview

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Flashcards in Chemistry 4: Chemical Patterns Deck (64)
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1

Atom

The basic 'building block' of an element which cannot be chemically broken

2

Periodic table

A table of all the chemical elements based on Thier atomic number

3

Element

Substance made out of only one type of atom

4

How was the periodic table developed

1. Mendeleev arranged elements into groups (vertical columns) and periods (horizontal rows) based on their relative formula mass and patterns in their properties
2. Mendeleev left gaps for undiscovered elements and predicted properties of missing elements
3. Johann döbereiner noticed 'triads' that linked patterns of the relative atomic masses for 3 elements
4. John Newlands noticed an 'octaves' pattern, where every 8th element had similar property's

5

How did scientists react to Döbereiner's and Newlands' theories

1. Scientists rejected Döbereiner's trains and Newlands' octaves because most elements did not fit their 'patterns'
2. When new elements were discovered, they fitted Mendeleev's predictions
3. Data about properties of elements in the periodic table can be used to work out trends and to make predictions

6

Line spectrum

A set of different coloured lines produced when the light from a burning element is passed through a prism

7

How did scientists react to Döbereiner's and Newlands' theories

1. Scientists rejected Döbereiner's trains and Newlands' octaves because most elements did not fit their 'patterns'
2. When new elements were discovered, they fitted Mendeleev's predictions
3. Data about properties of elements in the periodic table can be used to work out trends and to make predictions

8

Describe the discovery of helium using the line spectrum

1. The discovery of some elements, e.g. Helium, happened because of the development of spectroscopy
2. Helium was discovered when chemist looked at the line spectrum from the sun

9

Describe the properties of and atom

1. Atoms have tiny, central nucleus that contains protons and neutrons
2. Electrons travel around the outside of the atom
3. All the atoms of a particular elements have the same number of protons
4. Atoms have the same number of protons and electrons
5. The modern periodic table arranges atoms in order of their protons number

10

Describe the charge and mass of protons

Charge: + 1
Mass : 1

11

Describe the charge and mass of electron

Charge : -1
Mass: almost zero

12

Describe the charge and mass of neutron

Charge: 0
Mass: 1

13

How do we find the relative atomic mass

Number of protons + number of neutrons

14

How do are electron arranged

1. Electrons are arranged in shells around the nucleus
2. The 1st she'll is closed to the nucleus and can hold 2 electrons
3. The 2nd and 3rd shells are further away fro bathe nucleus
4. The second shell holds 8 electrons

15

Electron arrangement

The configuration of electrons in shells, or energy levels, in an atom

16

How does the energy levels relate to the electron shells

1. Electrons in different shells have different energy levels
2. The closer the electron shell is to the nucleus, the lower the energy level

17

Give an example for potassium with a proton number 19

2.8.8.1

18

What is a row in the periodic table called

Period

19

What happens to the number of electrons in the outer shell across a period

The number of electrons in the outer shell increases across a period

20

What Happen as you move left to right along a period

1. Elements change from metals to non-metals
2. Each element has 1 more origin and one more electron

21

Group 0 and their electron shells

Have full electron shells and are inert- this means they are very unreactive

22

Inert

An element that does now react with any other element

23

What does the number of electron in the outer shell mean

Number of electrons in the outer shell of an atom is the same as its group number on the Periodic Table

24

What are atoms of element with 3 electrons in their outer shell

Metals

25

What are atoms of elements with 5 or more electrons in their outer shell

Non-metals

26

What are elements with full outer shells

Inert gases

27

Groups

The vertical columns are called groups

28

Alkali metals

Very reactive metal in Group 1 of the Periodic Table e.g. sodium

29

What are group 1 elements called

1. Are called alkali metals

30

How hard are group 1 metals and what are their reactivity

2. Are soft metals that can be cut with a knife. The freshly cut surface is shiny but it tarnish quickly in moist air by reacting with oxygen
3. The reactivity of group 1 elements is linked to the single electron in the outer shell. They all form ions with a 1+ charge by losing an electron

31

How does the size of an atom affect group 1 elements

The outer electron is easiest to lose of the atom is bigger (because the electron is further from the nucleus). So reactivity increases down the Group 1 elements as the atoms gets bigger

32

How does a group 1 element react with water

Group 1 elements all react with water, e.g. lithium and sodium fizz and move around on the surface of the water. The reaction gets more violent as you move down Group 1, e.g. potassium explodes and rubidium explodes more violently

33

What are the safety issues with group 1 elements

Group 1 metals are flammable and their hydroxides are harmful and corrosive. When handling Group 1 metals they should be kept away from water

34

What is the word equation for when Group 1 elements react with water

Metal + water ➡️ metal hydroxide + hydrogen

35

What is the symbol equation for when Group 1 elements react with water

2M(s) + 2H₂O(l) ➡️ H₂ + 2MOH(aq)

36

What is the symbol equation for when sodium reacts with water

2Na(s) + 2H₂O(l) ➡️ H₂ + 2NaOH(aq)

37

How does sodium react with chlorine

Sodium reacts vigorously with chlorine to give a yellow flame; it makes a white solid (sodium chloride)

38

How does the group 1 metals react with sodium further down the group

The other group 1 metals tact in a similar way, and the reactions are faster down the group

39

What is the word and symbol equation for the reaction between sodium and chlorine

Sodium + chlorine ➡️ sodium chloride

2Na(s) + Cl₂(g) ➡️ 2NaCl(s)

40

What is the name of group 7 elements

Halogens

41

What is the appearance of the halogen - chlorine at room temperature and the colour of gas

Room temperature: pale green gas
Colour of gas: pale green

42

What is the appearance of the halogen - bromine at room temperature and the colour of gas

Room temperature: red-brown liquid
Colour of gas: reddish-brown

43

What is the appearance of the halogen - iodine at room temperature and the colour of gas

Room temperature: dark grey solid
Colour of gas: purple

44

What do halogens contain

Diatomic molecules. This means that they have 2 atoms joined together at each molecule

45

What are the physical properties of the halogens show a trend down the group

Melting points and boiling points increase

46

What are the dangers of group 7 elements

Group 7 elements are corrosive and toxic. They need to be used in a fume cupboard.

47

How do group 7 elements react with alkali metals

Group 7 elements react with alkali metals and with other metals such a iron to form metal halides

48

Halides

Compounds formed when halogens react with alkali metals and other metals

49

Metal + halogen ➡️

Metal halide

50

Iron + chlorine ➡️

Iron chlorine

51

Sodium + bromine ➡️

Sodium bromine

52

Potassium + iodine ➡️

Potassium iodide

53

How are halogens less reactive down the group, give examples

1. Sodium reacts vigorously in chlorine but reacts less violently with iodine
2. Iron reacts vigorously in contact with fluorine but reacts with iodine when heated
3. Fluorine reacts even more vigorously than other halogens

54

Displacement reaction

The difference in the reactivity of halogens. Where one halogen will take place of the another in its compounds

55

Give examples of a displacement reaction from. The group 7 elements

1. Chlorine is more reactive than bromine and displaced bromine from potassium bromide solution
2. Bromine is less reactive than chlorine and Connor displace chlorine from potassium chloride solution

56

How deist the trend in reactivity link to be number of electrons shells in an atoms for non metals

1. All halogen atoms have 7 electrons in their outer shell
2. The trend in reactivity is linked to the umber of electron shells in the atom. For non-metals, the smaller the atom ( the fewer the electron shells) the more reactive the element

57

What are ionic compounds

1. Compounds of a group 1 and a group 7 element (e.g. sodium chloride) are solids with high melting points
2. These compounds are ionic compounds because they contain charged particles, or ions, that are arranged in a regular pattern called a crystal lattice

58

Crystal lattice

Crystals formed by ionic compounds, such as sodium chloride, which have a regular pattern and shape

59

Explain the properties an ionic compound

1. Ionic compounds are solvable in water and conduct electricity when they are melted
2. When an ionic crystal melts or dissolves in water the ions are free to move
3. An ionic compound conducts electricity when molten or in a solution but not when solid. This is be had the ions must move to the electrodes to complete the circuit

60

How does a group 1 element become a positive ion

An atom of a group 1 element loses one electron to become a positive ion, e.g. Na becomes Na+

61

How does an atom of a group 7 element become a negative ion

An atom of a group 7 element gains an electron to become a negative ion, e.g. Cl becomes Cl^-

62

What happens when a group 1 metal become an ion

1. When a group 1 atom becomes an ion it loses one electron from its outer shell
2. All group 1 metals becomes an ion with a 1+ charge

63

What happens when a group 7 metal ion becomes an ion

1. When a group 7 element becomes an ion its gains one electron in its outer shell
2. All group 7 metals become ions with a 1- charge
3. This means that the ions have the same electron arrangement was an atom in group 0

64

How does the number of positive and negative charges relate in an ionic compound, and what does this mean

1. In the formula for an ionic compound the number of positive and negative charges balance, e.g. Na^+ and Cl ^- have one positive and one negative charge so form compound NaCl
2. You can work backwards from the formula to work out the charge on the ions, e.g. in CaCl₂ there are 2^- charges from the two Cl^- ions, so the calcium ion has a charge of Ca²^+