Chapter 4 chemistry

An ion from a given element has 16 protons and 18 electrons. What is the charge on the ion What is the name of the element What is the symbol for the ion

-2 Sulfur S-2

you write it like this:

3s2 3p4 (no space between the numbers)

The element in period 3 that has this valence electron congfiguration

X> = Na (sodium)

An ion with a negative charge is called an

anion

An ion with a positive charge is called an

cation

element group is the number of dots

example: 7a = 7 dots

the number of valence electrons is equal to the group number.

example: Row 2A = >x> (those are dots) number of dots = number of valence electrons = group number

more examples:

Group 2A/2nd period Be(s)2 or Group 8A/3rd period Ar = 3s2 3p6

Write the formula for aluminum oxide

Ions: Al3+ and O2- Formula: Al2O3

Write the formula for copper(II) chloride

Ions: Cu2+ and Cl- Formula: CuCl2

Write the formula for ammonium carbonate

Ions: NH4+ and CO32- Formula: (NH4)2CO3

An ion from a given element has 83 protons and 80 electrons. What is the charge on the ion What is the name of the element What is the symbol for the ion

ion = +3 Bismuth Bi+3 (because you subtract 83-80=3 left over which is 3 more or +3 (plus 3 is the ion charge)

valance configuration is

n (examples.... group 1 period 1 = ns1 or group 6 period 1 = ns2 p 4 (1st s always has 2 then p has the rest)

An ion from a given element has 55 protons and 54 electrons

since more protons than electrons.....subtract but ion is 54 (you have to give back the difference)