Chapter 2

Question 1

atoms

Answer 1

elements are composed of extremely small particles called atoms

atoms can be identified by the number of protons and neutrons they contain

Atomic number = number of protons
Number of protons = number of electrons
mass = no of protons + no of neutrons

Question 2

electronical configuration

Answer 2

is the distribution of electrons in the vary energy levels

Question 3

workout in which group an element is in by

Answer 3

the number of electrons in its out most energy level determines the valence. the valance is the number of electrons it will gain of lose

Question 4

isotopes

Answer 4

are two or more atoms that have the same atomic number but different mass

Question 5

Radioactivity

Answer 5

Takes place through nuclear fusion
This releases heat energy and various forms of radioactive radiation
Unaffected by temp of whether isotope is part of a compound or present as the free element
Radioactive decay is a nuclear process not a reaction

Question 6

Uses of radioactivity industry

Answer 6

Radioactive isotopes are widely used in the industry and medicine, uranium as it splits being bombarded with neutrons, huge amounts of energy is produced

-monitoring the level of filling in containers, checking thickness of sheets of plastic, paper or metal fossil
And defy leaks in gas or oil pipes

Question 7

Uses of Radioactivity in medicine

Answer 7

Biological cells are sensitive to radioactive emissions

Cobalt-60 used to tear internal cancer tumors
And medical instruments, dressings and syringes can be sterilized by sealing them in polythene bags and exposing them to intense doses of y-radiation