C1 Periodic Trends

What is the smallest part of an element that can exist?

an atom

What is an element?

A substance made up of only one type of atom

What is a compound?

A substance made up of two or more different types of atom that are chemically bonded together

What is a mixture?

A substance made up of two or more elements or compounds that are not chemically bonded together

What is a molecule?

A substance made up of two or more atoms that are chemically bonded together

How would you separate an insoluble solid from a liquid?

Filtration

How would you separate two liquids?

Distillation

How would you separate a mixture of coloured compounds?

Chromatography

What is the plum pudding model of the atom?

the atom is a ball of positive charge with negative electrons embedded in it

What is the nuclear model of the atom?

the atom contains a charged nucleus in the centre which contains most of the mass of the atom

What conclusions were drawn from the alpha particle scattering experiment?

The mass of an atom is concentrated in the nucleus and the nucleus is charged

Who adapted the nuclear model to included electron shells?

Niels Bohr

What was Niels Bohr's contribution to the atomic model? (2)

He suggested that electrons orbit the nucleus at specific distances

His theoretical calculations agreed with experimental observations

Who provided the evidence to show neutrons existed?

James Chadwick

What was James Chadwick's contribution to the atomic model? (2)

He provided the evidence to show the existence of neutrons within the nucleus

This was about 20 years after the nucleus became an accepted scientific idea

What is the relative charge of an electron?

-1

What is the relative charge of a neutron?

0

What is the relative charge of a proton?

1

What is the charge of the nucleus of an atom?

Positive

What is the charge of an atom?

Neutral

What is the relative mass of a proton?

1

What is the relative mass of a neutron?

1

What is the relative mass of an electron?

Very small (close to 0)

Where in atoms are protons found?

nucleus

Where in atoms are neutrons found?

nucleus

Where in atoms are electrons found?

Electron shells

What does the mass number of an atom represent?

The number of protons and neutrons in the nucleus of an atom

What does the atomic number of an atom represent?

The number of protons in the nucleus of an atom

How can you work out the number of electrons in an atom?

It will be the same as the number of protons

How can you work out the number of protons in an atom?

It is the atomic number

How can you work out the number of neutrons in an atom?

mass number - atomic number

What is relative atomic mass?

The average mass of all the atoms of an element

How many electrons does the first electron shell hold?

2

How many electrons does the second electron shell hold?

8

How many electrons does the third electron shell hold?

8

How are elements arranged in the periodic table?

By increasing atomic (proton) number

What are the rows in a periodic table called?

periods

What are the columns in a periodic table called?

groups

What does the group number tell you about elements?

the number of electrons in the outer shell

What do elements in the same group have in common?

they have similar properities

Why do elements in the same group have similar chemical properties?

they have the same number of electrons in their outer shell (outer electrons)

Who developed the modern periodic table?

Mendeleev

Why did Mendeleev leave gaps in his periodic table?

For undiscovered elements

How did Mendeleev arrange the periodic table? (2)

in order of increasing atomic weight

however, he changed the order for some elements based on their properties

Where are metals found on the periodic table?

To the left hand side

Where are non metals found on the periodic table?

To the right hand side

What charge do metal ions have?

Positive

What charge do non metal ions have?

Negative

How do metals form ions?

lose electrons

How do non metals form ions?

They gain electrons to form negatively charged ions

What is the name of the elements in group 0?

noble gases

Why are group 0 elements unreactive?

their atoms have stable arrangements of atoms (full outer shells)

How does the boiling point of group 0 elements change as you go down the group?

Boiling point increases

What is the name of the metals in group 1?

alkali metals

How many electrons do group 1 metals have in their outer shell?

one

Why do group 1 metals have similar characteristic properties?

they all have one electron in their outer shell

How does the reactivity of group 1 metals change as you go down the group?

They get more reactive

What is the name of the elements in group 7?

halogens

How many electrons do group 7 elements have in their outer shell?

7

Why do group 7 elements have similar characteristic properties?

they all have seven electrons in their outer shell

How does the mass of group 7 elements change as you go down the group?

mass increases

How does the melting and boiling point of group 7 elements change as you go down the group?

increase

How does the reactivity of group 7 elements change as you go down the group?

less reactive

What is a displacement reaction?

A reaction in which a more reactive element takes the place of a less reactive element in a compound