Chemistry - Unit 9, Periodic Table and Trends

What is a period?

horizontal row in the periodic table

What is a group?

vertical column in the periodic table

What did Dobereiner discover?

he discovered triads

What did Newlands change about the periodic table?

he arranged elements by atomic mass without leaving gaps, he also created law of octaves

What did Meyer change about the periodic table?

he arranged the elements by valency number of bonds) and only included a subset of elements

What did Mendeleev change about the periodic table?

he arranged the elements by atomic mass and chemical and physical properties while leaving gaps for unknown elements. he also made predictions about unknown elements - he is credited for the periodic table

What did Moseley change about the periodic table?

he arranged the elements by atomic number - father of the modern periodic table

What did Seaborg discover with the periodic table?

he discovered many transuranium elements (elements past uranium) which proposed the f-block

What is the periodic law?

properties of elements repeat as a function of atomic number

What are characteristic of metals?

elements that lose electrons easily, shiny, good conductors of heat and electricity, maleable (change form without breaking it), solid at room temp.

What are characteristic of nonmetals?

different colors, solids, liquids or gases, brittle, do not conduct heat or electricity

What are characteristic of metalloids?

have properties of metals and nonmetals - silverish, brittle, poor conductors

What are characteristic of alkali metals?

group 1 - very reactive, violently reacts with water, soft, low density

What are characteristic of alkaline earth metals?

group 2 - reactive but less reactive than alkali metals, slowly reacts with water

Are halogens reactive?

group 17 - yes, they are very reactive

Are noble gases reactive?

group 19 - no, they are virtually non reactive

What block are transition metals in?

d-block, common metals

What block are post-transition metals in?

p-block, larger elements below the metalloid line

What block are lanthanoids in?

f-block, elements after La

What block are actinoids in?

f-block, elements after Ac

What is the octet rule?

8 valence electrons means chemical stability

What are isoelectronic species?

atoms and ions have the same number of electrons and the same electron configuration

What is an atomic radius?

the distance from the nucleus to the outermost electron(s)

What is metallic character?

how easily an atom loses electrons

What is ionization energy?

energy required to remove one electron from an atom

What is electronegativity?

ability of an atom to attract electrons while in a compound (in the bond)

What are blocks of elements according to the type if the last orbital being used?

s-blocks, p-blocks, d-blocks, and f-blocks