Lesson 3 Flashcards
1
Q
How many elements found in nature?
A
118
2
Q
Define atoms
A
Atoms are the smallest uniquely distinguished particles
3
Q
Define what atomic number is
A
The number of protons in the nucleus of an atom
4
Q
Define what mass number is
A
The total mass of the atom = number of protons and neutrons
5
Q
Formula for neutrons
A
Neutrons= mass number - atomic number
6
Q
What is an isotope?
A
A form of an element that has the same number of protons but a different number of neutrons in its nucleus
7
Q
Write down relative atomic mass equation
A
(Massabundance)+(Massabundance) /100
8
Q
What is the relative mass of electron? (From the table)
A
1/1836
9
Q
What is the atomic number of Br?
A
35
10
Q
Why the number of protons must be equal to number of electrons?
A
Because atoms are electrically neutral
