Unit 1 Flashcards
what is an element?
any substance that cannot be decomposed into simpler substances by ordinary chemical processes (identical atoms)
What is a compound?
a substance made up of two or more different chemical elements
What is a pure substance?
an element or compound made up of one type of particle
What is a mixture?
a material made up of two or more different chemical substances which are not chemically bonded
what is heterogeneous?
mixtures that have visually distinguishable components
what is homogeneous?
appears uniform throughout
Define Atomic Number
The number of protons in the nucleus (charge)
Define Mass Number
The number of protons and neutrons in an atom (mass number = protons + neutrons.)
Define Isotope
Atoms that have different numbers of neutrons
What is the “Period Law” ?
elements that are arranged in order of increasing atomic number
Where are metals in the periodic table?
Metals are located on the left of the periodic table (separated by staircase)
Where are nonmetals in the period table?
nonmetals are located on the upper right. (separated by staircase)
What types of elements form ionic compounds?
Ionic compounds are (usually) formed when a metal reacts with a nonmetal (or a polyatomic ion)
What types form covalent compounds?
Covalent compounds are formed when two nonmetals react with each other
which was does atomic radius decrease?
Left to right
which way does atomic radius increase?
Top to Bottom
why does the atomic radius decrease left to right?
the more electrons in the outer energy level means there will be a greater attraction between the outer energy level and the nucleus
Why does the atomic radius increase top to bottom?
Each new period means another energy level, which means a larger atom
What is ionization energy
the amount of energy required to remove an electron from an isolated atom or molecule
Which has more ionization energy?
Non metals or Metals?
I.E. of non metals are generally higher than I.E. of metals
which way does Ionization energy increase
left to right in a period
why does the Ionization energy increase Left to right?
the decrease in atomic size
which way does ionization energy decrease?
down a group
Why does Ionization energy decrease top to bottom
increase in atomic size
