Y9 Chemistry - Atomic structure, Chemical bonding and Properties of Matter

Definition of atom?

All substances are made of atoms. An atom is the smallest part of an element that can exist.

What are atoms of each element represented by?

a unique chemical symbol

How many types of atom does each element contain ?

only 1

Are molecules metal or non metal?

Non metal

Are molecules all or some non metals?

Some

How to tell whether an element is an atom or a molecule?

Subscripted number, eg 2

How are compounds formed?

From elements by chemical reaction

Compound definition?

A compound contains 2 or more elements bonded together in fixed proportions.

How are compounds represented

They can be represented by formulae using the symbol from the atoms from which they were formed, eg NaCl - sodium chloride

In which ways can chemical reactions be written?

Word or symbol equations

What is true of the first letter in Element symbols?

The first letter is always capital.

What is the radius of an atom?

Very small, 0.1 nanometres (10^-10)

What is the radius of an atomic nucleus?

Less than 1/10000 of that of an atom (10^-14)

What is the overall electric charge of an atom?

Neutral, because protons = electrons

Do atoms of different elements have different amounts of protons?

Yes, and same for electrons and neutrons.

What is the atomic number?

Number of protons = number of electrons.

What is the mass number?

Number of protons + neutrons in the nucleus

What is an isotope?

An element that has a different relative atomic mass due to a different number of neutrons.

Definition of relative atomic mass?

Relative atomic mass is the number of protons and neutrons in the nucleus of all thé isotopes in an element compared to Carbon

Why is relative atomic mass compared with Carbon-12?

Because Carbon-12 is the standard atom.

Where are the protons, neutrons and electrons?

The protons and neutrons are in the nucleus, the electrons orbit in shells.

Which force keeps the electrons orbiting the atom?

Positives and Negatives attract

What is each elemeant defined by

Atomic number

Define isotope

Atoms of the same element (same number of protons) with different number of neutrons (different mass number

What are chemical properties of elements

The way in which they react

What are physical properties of elements

Boiling and melting points, looks, etc

What do chemical properties of elements depend on

Number of electrons

Will different isotopes of the same element react in the same way or in a different way

Same way

What is the universal atom

Carbon-12

What 4 things do isotopes have the SAME as normal elements

Number of protons, number of electrons, atomic number, chemical properties

What 3 things do isotopes have that DIFFER from normal elements

Number of neutrons, mass number, physical properties

Formula for relative atomic mass

Relative atomic mass (Ar) = sum of (isotope abundance x isotope mass number) / sum of abundances of all the isotopes