Chemistry ✿ Atomic structure and the periodic table

what does the nucleus consist of?

protons and neutrons

the number of protons can also tell you the number of _________

electrons

ion

an atom that has lost or gained electrons

how to find the number of neutrons in an elements?

mass number - atomic number

elements

a substance that only has one type of atom

isotopes

different forms of elements which have the same number of protons but different number of neutrons

compounds

a substance that has two or more elements that are chemically combined

mixture

a substance that has two or more different elements, not chemically bonded

state 3 features the plum pudding model

• a solid sphere of positive charge

• mass was spread out

• negative electrons embedded

In the alpha scattering model, what where the results and what did it say about the atom? which model did it lead to?

• particles were deflected → because of positive nucleus

• particles went straight through → empty space in atom

• particles were reflected → mass is concentrated in the centre

• led to the nuclear model

state 3 features the nuclear model

• mass is concentrated in the centre

• electrons orbit nucleus in shells

• positive charged nucleus

who found the existence of neutrons?

James chadwick

who found the existence of the nucleus?

Rutherford

who found the existence of shells?

Neil Bohr

the period number shows how many ______ there are in the element

shells

the group number shows how many _______ there are on the outer shell

electrons

insoluble

cannot dissolve in liquid

soluble

can dissolve in liquid

what charge do atoms have overall? why?

neutral

positive protons and negative electrons cancel each other out

Non metals are located at the _____ side of the periodic table

right

give 3 properties of a metal

• metallic bonding

• high boiling/ melting point

• conduct heat and electricity

give 3 properties of non metals

• no metallic bonding

• low density

• brittle

what are the group 1 elements called?

alkali metals

name 3 trends in group 1 as you go down

• increasing reactivity

• decreasing melting/ boiling points

what is the radius of the atom?

0.1nm (1 × 10^-10 m)

what is the radius of the nucleus?

10,000 times smaller than atom (1 × 10^-14 m)

How do the alkali metals react with oxygen? what do they produce?

act vigorously as you go down the group and tarnish

produce a metal oxide

How do the alkali metals react with chlorine? what do they produce?

act vigorously as you go down the group and tarnish

produces metal chlorides

What do the alkali metals produce when they react with water?

metal hydroxide

How does lithium react with water? [3]

• fizzes

• produces hydrogen gas

• floats and moves above water surface

How does sodium react with water? [2]

• fizzes vigorously

• floats and moves above waters surface quickly

How does potassium react with water? [3]

• produces lilac flame

• fizzes vigorously

• floats and moves above waters surface quicky

why does the reactivity increase as you go down the group 1 metals? [3]

• as you go down the group, the outermost shell is further away from the nucleus

• there is less attraction between the nucleus and the electron

• so the electron is lost easily

what does the reactivity of a metal of an element depend on?

the ability to lose an electron on the outermost shell

what does the reactivity of a non-metal of an element depend on?

the ability to gain an electron on the outermost shell

what are the group 7 elements called?

halogens

name 3 trends in group 7 as you go down

• atoms increase in size

• boiling and melting point increase

• reactivity decreases

why does the melting and boiling point increase as you go down the group 7 gases? [3]

• as you go down group 7, atoms increase in size

• stronger intermolecular forces between atoms

• more energy is required to break the forces

why does the reactivity decrease as you go down the group 7 gases? [3]

• as you go down group 7, the outermost shell is further away from the nucleus

• there is less attraction between the nucleus and the electron

• so the outermost shell is is less likely to gain an electron

how do the halogens (group 7) react with a metal and a non-metal?

gain an electron when they react with metals and form ionic bonds

share one pair of electrons when they react with non-metals and form covalent compounds

displacement reaction

reaction where a more reactive element replaces the less reactive element in a compound

What are the group 0 elements called?

noble gases

state 3 properties of the noble gases

inert

stable arrangement of electrons

8 electrons in outermost shell (except helium)

Why does boiling point increase as you go down group 0? [3]

• as you go down group 0, atoms increase in size

• there is stronger intermolecular forces between atoms

• so more energy is required to break the bonds