Science Atomic structure

Question 1

Compare and contrast a chemical change with a physical change

Answer 1

Physical- no new substance is formed only physical state changes e.g Solid to liquid
Chemical- a new substance is formed e.g colour changes

Question 2

Explain how elements are arranged in the periodic table
clue: metal and non-metal

Answer 2

The chemical elements are arranged in order of increasing atomic number.

The rows (across the table) are called periods and the columns (down the table) are called groups.

Metals are found on the left side of the periodic table and nonmetals found on the right side of the periodic
table.

Question 3

Relate the valence electrons and electron configuration to the group the element is in, in the periodic table.
clue: group 2= 2 v group 13 = 3 v

Answer 3

Group 1 = 1 valence electron
Group 2 = 2 valence electron
Group 13 = 3 valence electrons
Group 14 = 4 valence electrons
Group 15 = 5 valence electrons
Group 16 = 6 valence electrons
Group 17 = 7 valence electrons
Group 18 = 8 valence electrons

Question 4

Name and state the symbols of common elements in the periodic table first 20 and, Ag, Au, Ba, Br, Cu, Fe, Pb and Zn

Answer 4

H = Hydrogen He = Helium
Li = Lithium Be = Beryllium
B = Boron C = Carbon
N = Nitrogen O = Oxygen
F = Fluorine Ne = Neon
Na = Sodium Mg = Magnesium
Al = Aluminium Si = Silicon
P = Phosphorus S = Sulfur
Cl = Chlorine Ar = Argon
K = Potassium Ca = Calcium

Cu = Copper Ag = Silver Au = Gold Fe = Iron Ba=Barium Br=Bromine Zn = Zinc Pb = Lead

Question 5

Calculate the number of protons, neutron and electrons in an atom, given the mass number and atomic number

Answer 5

The atomic number of an atom shows how many protons it has in its nucleus. The number of electrons an atom has is the same as the number of protons as the atom is neutral overall. The number of neutrons can be calculated by subtracting the atomic number of an atom from its mass number. For example, Li: 3p+ , 3e- & 4 neutrons.

Question 6

Explain why atoms are neutral overall

Answer 6

Atoms have the same number of protons (+1 charge) and electrons (-1 charge). Therefore these cancel each other out and the atom has no overall charge making it neutral.

Question 7

. Describe ionic & covalent bonding

Answer 7

Ionic bonding occurs between two oppositely charged ions that are attracted to one another due to electrostatic
forces. To form the ions, an (metal) atom will lose valence(s) to form a full valence shell and become stable.
The electron(s) lost will be gained by another (non-metal) atom for it to have a full valence shell and become
stable. This forms the anion and cation which form the ionic bond and result in an ionic compound.

Covalent bonding occurs between two or more non-metal elements. They cannot form a bond by transferring
electrons from one to another; instead, they share electrons so that each atom has a full valence shell. This is
called a covalent bond.

Question 8

Explain ionic & covalent compounds in terms of their bonding and type of elements

Answer 8

Ionic bonding occurs between a metal and a non-metal. Metals are located on the left side of the periodic table
and non-metals are located on the right side of the periodic table. Due to metals forming cations when they
react and the non-metals form anions when they react this creates an electrostatic force of attraction between
the oppositely charged ions and forms the ionic bond.

Non-metal elements are located on the right hand side of the periodic table and they will form covalent bonds with each other to fill their valence shells.