atomic structure, isotopes and formulae Flashcards
What was stated in Dalton’s atomic theory?
- Atoms are tiny particles made of elements
- Atoms cannot be divided
- All the atoms in an element are the same
- Atoms of one element are different to those of other elements
What is the relative mass of a proton
1
Define molecular ions
Covalently bonded atoms that lose or gain electrons
How do you calculate the number of neutrons?
mass number - atomic number
What is the charge of the ion when electrons are gained?
Negative
Define relative isotopic mass
The mass of an atom of an isotope compared with 1/12th of the mass of an atom of carbon-12
Explain how to calculate the empirical formula
- Divide amount of each element by mr
- Divide answers by smallest obtained value
- If it is a decimal divide by suitable number to get a whole number
Which letter represents the mass number?
A
Explain the current model of the atom
- Protons and neutrons are found in the nucleus
- Electrons orbit in shells
- Most the atom is empty space between the nucleus and the electrons
What were Rutherfords proposals after the gold leaf experiment?
- Most of the mass and positive charge of the atom are in the nucleus
- Electrons orbit the nucleus
- Most of atom’s volume is space between the nucleus and the electrons
- Overall positive and negative charges must balance
How is the mass number calculated?
number of protons + number of neutrons
Why do different isotopes of the same element react in the same way?
- Neutrons have no impact on the chemical reactivity
- Reactions involve electrons, isotopes have the same number of electrons in the same arrangement
What are the 4 elements that don’t form ions and why?
- The elements: beryllium, boron, carbon and silicon
- Require a lot off energy to transfer outer shell electrons
What letter represents the atomic number of an atom?
Z
The relative isotopic mass is the same as which number?
Mass number
What does the atomic number tell us about an element?
The number of protons in an atom
What is the charge of a proton?
1+
What is the relative mass of an electron
1/2000
How is the periodic group number related to the number of electrons?
Represents the number of electrons in an atoms outer shell
Define ions
Charged particles that are formed when an atom loses or gains electrons
How to calculate the relative molecular mass and the relative formula mass?
Add up the relative atomic masses of each of the atom making up the molecule/formula
Define relative atomic mass
The weighted mean mass of an atom of an element compared with 1/12th of the mass of 1 atom of carbon-12
What did Thompson discover about electrons?
- They have a negative charge
- They can be deflected by magnets and electric fields
- They have a small mass
What is the relative mass of a neutron
1
