Studied by 50 people________= given mass of compound /sum of mass numbers of the elements present in a compound.
Mole
Compound molecules
________ are created when specific proportions of atoms from several elements combine.
Metals
________ and some other elements, such as carbon, do not have a simple structure but consist of a very large and indefinite number of atoms bonded together.
An atom consists of a(n) ________ that is surrounded by one or more negatively charged electrons.
central nucleus
A(n) ________ is a particle of matter that uniquely defines a chemical element.
atom
helium
Many elements have only one atom per molecule, including ________ (He), argon (Ar), and others.
constituent particles
Positively charged sodium ions (Na+) and negatively charged chloride ions (Cl)- make up its ________.
________ can be used to find out how the atoms of an element will combine with the atom (s) of another element to form a chemical compound.
Valency
chemical reactions
Atoms, the incredibly small building blocks of all matter, take part in ________.
A negatively charged ion is called ________
anion
Atomic radius
________ is measured in nanometres.
Atoms
________ create ions and molecules.
different elements
A molecule can be created by joining together atoms of the same element or of ________.
________ are created when atoms join in a ratio of small whole numbers.
Compounds
A(n) ________ is an association of charged atoms.
polyatomic ion
The ________ was the most astonishing idea Dalton's atomic theory provided.
atomic mass
chemical reaction
In a(n) ________, atoms can not be formed or destroyed since they are indivisible particles.
Eg In a compound such as water, the ratio of the mass of hydrogen to the mass of oxygen is always 1
8, whatever the source of water
Carbon dioxide (CO2 ) Carbon, Oxygen 3
8
Ammonia (NH3 ) Nitrogen, Hydrogen 14
3
Water (H2O) Hydrogen, Oxygen 1
8
Its formula unit mass can be calculated as
1 × 23 + 1 × 35.5 = 58.5 u
During a chemical reaction, the sum of the _________ of the reactants and products remain unchanged.
Masses
Ionic compounds are formed by the combination between ________ an ______.
Metal and non- metals
Mole is a link between the __________ and __________.
Mass of atoms & number of atoms
Those ions which are formed from single atoms are called _________.
simple ions
In a pure chemical compound, elements are always present in a ________ proportion by mass.
definite
The SI unit of amount of a substance is __________.
mole
The valency of an ion is _________ to the charge on the ion.
equal
The abbreviation used for length names of elements are termed as their _______.
symbol
Note
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