you could use this and just paint it.

http://en.wikipedia.org/wiki/File:Periodic_table.svg

similar to the countries there:
https://forum.processing.org/topic/mapping-abstract-shape-co-oridinates-i-e-countires-in-a-flat-world-map#25080000002281091

aoife38, I have moved all of your posts to General Discussion since they were just randomly placed in different sections of the forum. To know where to post a thread, please read: https://forum.processing.org/topic/where-to-place-threads-and-other-forum-practices

I found a data file that might help if you want to build the table from scratch:

you ***can create it from scratch but it's a horrible mess, because the table is so irregular.

I didn't even apply the correct colors...

It's using your 1st csv-file (optional)

1. //
2. final boolean DEBUG = true;
3. final color black = color(#000000);
4. final int gridx = 18; // number of cells in x direction
5. final int gridy = 9; // number of cells in x direction
6. final int sizeX=42; // size
7. final int sizeY=42;
8. Cell [][]coor = new Cell[gridy][gridx];  // grid
9. //
10. void setup () {
11.   size (900, 600);
12.   background (black);
13.   // frameRate(5);
14.   //
15.   String[] a  = loadStrings ("periodic_table.csv");
16.   //println (a[3]);
17.   //
18.   // make grid
19.   int countInternal = 1;
20.   int atomic_number = 1;
21.   int addY=0;
22. 
    
23.   for (int j = 0; j<gridy; j++) {
24.     for (int i = 0; i<gridx; i++) {
25. 
    
26.       boolean exists=true;
27.       if (countInternal>1&&countInternal<18) exists=false;
28.       if (countInternal>20&&countInternal<31) exists=false;
29.       if (countInternal>38&&countInternal<49) exists=false;
30.       if (countInternal>=127&&countInternal<130) exists=false;
31.       if (countInternal>=145&&countInternal<148) exists=false;
32.       //
33.       //  this is for the two little empty fields Lanthanides & Actinides
34.       boolean special = false; // normal field
35.       if (countInternal==93||countInternal==111) {
36.         special=true; // empty field
37.         atomic_number+=14;
38.       }
39.       //
40.       // the lower two lines for Lanthanides & Actinides
41.       if (j>=7) addY=22;
42.       //
43.       // if it is there read file "periodic_table.csv"
44.       String name="";
45.       if (a!=null) {
46.         name="";
47.         if (exists&&!special) {
48.           if (atomic_number<118) {
49.             String temp=a[atomic_number-1];
50.             String[] parts= split(temp, ',');
51.             println (temp);
52.             if (!temp.equals(""))
53.               name =parts[3];
54.           }
55.         }
56.       }
57.       //
58.       coor[j] [i] = new Cell ( i *  (sizeX) + 72, j  *  (sizeY) + 42+addY,
59.       color (random (255), random (255), 0),
60.       atomic_number,
61.       exists,
62.       special,
63.       countInternal,
64.       name );
65.       //
66.       // if exists, increase atomic_number
67.       if (exists)
68.         atomic_number++;
69.       // this gets always increased
70.       countInternal++;
71.     }
72.   }
73. }
74. //
75. void draw () {
76.   background (black);
77.   //
78.   // show grid
79.   for (int j = 0; j < gridy; j++) {
80.     for (int i = 0; i < gridx; i++) {
81.       coor[j] [i].display();
82.     }
83.   }
84.   textSize(12);
85.   text ("Lanthanides", 50+50, height-243+20);
86.   text ("Actinides", 50+50, height-200+20);
87.   // we assign one new color
88.   //  int randoX = int (random(coor.length)); // rando = random number from array coor
89.   //  int randoY = int (random(coor[1].length)); // rando = random number from array coor
90.   //  coor [randoX][randoY].colCell= color (random (255), random (255), random (255));
91. }
92. //
93. void keyPressed() {
94.   //
95. }
96. void mousePressed() {
97.   //
98. }
99. // =======================================================================
100. class Cell {
101.   // one cell is one element
102.   int atomic_number;
103.   float mass_number;
104.   String name;
105.   String symbol;
106.   boolean exists=false;
107.   boolean special=false;
108.   float x;
109.   float y;
110.   float w=sizeX; //width/gridx-10;
111.   float h=sizeY; //height/gridy-10;
112.   color colCell;
113.   int  countInternal;
114.   //
115.   Cell (  float x_, float y_,
116.   color c_, int countExternal_,
117.   boolean exist_, boolean special_,
118.   int countInternal_,
119.   String name_ ) {
120.     x=x_;
121.     y=y_;
122.     colCell=c_;
123.     atomic_number=countExternal_;
124.     exists=exist_ ;
125.     special=special_;
126.     countInternal=countInternal_;
127.     name=name_;
128.   }
129.   //
130.   void display () {
131.     if (exists) {
132.       fill(colCell);
133.       stroke(255);
134.       rect(x, y, w, h);
135.       fill(255);
136.       textSize(12);
137.       if (!special) {
138.         text(atomic_number, x+16, y+18);
139.         text(name, x+16, y+28);
140.       }
141.       if (DEBUG) {
142.         textSize(8);
143.         text(""+countInternal+"", x+12, y+34);
144.       }
145.     }
146.   }
147.   //
148. } // class
149. // =======================================================================

Impressive work,  Chrisir.  I think it would be easier if you could find (or build) a file that contained the period & group number for each element.  That would make it almost as easy as placing each element at the correct x,y coordinates.

Thank you!