Topic 1 - Atomic structure and the periodic table

What does the Nucleus of an atom contain?

Protons and Neutrons

What charge does the nucleus of an Atom have… and why?

A positive charge because of the protons

What is concentrated in the nucleus of an Atom?

Almost the whole mass of the atom?

What are electrons?

They move around the nucleus in electron shells, they’re negatively charge and electrons have virtually no mass. The volume of their orbits determines the size of the atom.

What is the Relative charge and mass for a proton?

Relative mass = 1, Relative charge = +1

What is the Relative charge and mass for a Neutron?

Relative mass = 1, Relative charge = 0

What is the Relative charge and mass for an Electron?

Relative mass = Very small, Relative charge = -1

Why do atoms have no charge?

They have the same number of protons and electrons.

What is an ion?

A charged particle

Why are ions charged?

They don’t have the same number of electrons and protons

What does the atomic number tell us?

The number of protons

What does the mass number tell us?

How many protons + neutrons there are

What decides the type of atom it is?

Number of protons

What are elements?

Made up of the same type of atoms - all the atoms of a particular element have the same number of protons.

What can isotopes be defined as?

Different forms of the same element which have the same number of protons, but a different number of neutrons.

What is relative atomic mass in terms of isotopes?

is an average mass taking into account the different masses and abundances of all the isotopes that make up the element.

What is the equation for the relative atomic mass in terms of isotopes?

sume of(isotope abundance X isotope mass number)/sum of abundances of all the isotopes

What are compounds?

Compounds are substances formed from two or more elements and are held together by chemical bonds.

How do you separate the original elements of a compound?

A chemical reaction is required, and tends to be difficult to separate them

Compare the properties of a compound and the properties of the original elements?

Totally different

What are mixtures?

Two or more substances that are not chemically joined together

Separation techniques?

Who created the first atomic model?

John Dalton

1. When did John Dalton create this atomic model? And what did he theorise?

2. Who and when was the next scientist to create another atomic model? What did he theorise?

3. Who and when concluded that the plum pudding model was wrong?

1. 1803. He described the atoms as solid spheres and said that different spheres made up different elements.

2. 1897. JJ Thomson concluded from his experiments that atoms weren’t solid spheres. His measurements of charge and mass created the plum pudding model, which was a ball of positive charge with electrons stuck in it.

3. in 1909, Ernest Rutherford conducted the alpha particle scattering experiment. He fired positively charged alpha particles at an extremely thin sheet of gold. Some alpha particles were deflected backwards - more than they expected. Leading to an idea that there was a positively charged nucleus. With a “cloud” of negative electrons floating around this.

What was Neil Bohr’s nuclear model for the atom?

He proposed that electrons orbit the nucleus in fixed shells.

Who discovered the idea of neutron? And when?

In 1932, James Chadwick

What is the rule for electronic structure

1st Shell = 2, 2nd shell = 8, 3rd Shell = 8