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Liquid metal element
Mercury
Liquid non-metal element
Bromine
Substance its molecules consist of similar atoms
Element
Substance its molecules consist of different atoms
Compound
Scientist who arranged elements according to atomic mass
Mendleeve
Substance consists of two or more substances not chemically combined
Mixture
The outermost energy level of metals contains ............... electrons but non-metals contains ............... electrons
less than 4 - more than 4
A group of gases of zero gtoup
Inert gases
mixture its components can not be distingushed by naked eye
Homogeneous mixture
Thebuilding unit of matter
Atoms
The elements of p-block begins with .......... group and ends with ........... group
3A - Zero
The atom is electrically neutral (GR)
Because number of positive protons = number of negative electrons
The valency of inert gases is zero (GR)
Because their outermost energy level is completely filled
The
M level is filled with electrons before N level (GR)
because energy of M is less than energy of N
Elements of the same group have similar properties (GR)
Because all have the same number of electrons in outermost energy level
Mass number is always graeter than atomic number (GR)
Because mass number is the number of protons and neutrons but atomic number is protons only
