Chemistry Flashcards
What is an element
A substance made up of one type of atom. So cannot not be split up into smaller substances
How many elements are in normally present in the human body?
26
What are the four major elements
Carbon, hydrogen, oxygen and nitrogen
What are subatomic particles ?
Protons, neutrons and electrons
What does the proton and neutron form ?
The nucleus of an atom
What charge does a proton have and what is the mass?
Positive charge and a mass of approximately 1 atomic unit
What charge does a neutrons have and what is the mass?
A neutron have no charge and has a mass of 1 atomic unit
What charge does a electron have and what is the mass?
An electron is negatively charged and buzz around the outside of the nucleus. Creating an electron cloud. They have virtually no mass
How many electrons and protons does an element have ?
Equal number of protons and electrons resulting in a overall negative charge
What is an electron shell?
Groups of electrons that move around the nucleus
Where do the electrons pair up ?
Within their shells
When does an atom become reactive?
If it’s outer shell isn’t full or if it loses an electron
What is a free radical ?
When a atom loses an electron and the electron is unpaired
What are the chemicals properties of an atom reliant on ?
The number of protons and electrons
What is a periodic table?
A list of the currently known elements arranged in columns and rows that show us which elements share similar reactivity and physical properties
What does the number assigned to each element mean ?
How many protons ,and therefore how many electrons each atom has
What does the larger number indicate?
The mass number - weight in atomic units.
It tells us how much the atom weighs so can be used to work court the number of neutrons-as the electron weigh nothing
atoms have to be in even numbers
2, 8, 8
Period table explain
small number is atomic number
The larger number is
Any atom will always be neutral as the protons and atoms cancel each other out.
The outer shell determines where an atom is in the periodic table
E.eg Sodium has 1 in the outer shell therefore in group 1
Noble gases
outer shell always has 8
Halogens
Always have 7 in the outer shell
Isotope, why does it act in the same why ?
Atoms of the same element with different number of neutrons, because it has the same amount of protons and neutrons
Radiation comes from isotopes
Because unstable neutrons that get rid of the neutrons -becomes radioactive, gamma, alpha and beta
